5 personal finance tips I wish I knew before turning 18

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At the start of my freshman year of college, I quickly faced a harsh reality — I needed to learn how to manage my money better. I had always saved as much as possible from birthday money to my first paycheck, but it felt like college came with endless expenses I needed to budget for.

Now, in my third year of college, I have learned numerous ways to set myself up for financial success and make the most out of my money. Here are a few lessons I wish I had known before turning 18.

A strong credit history is important when buying your first car, home or other large purchase requiring a loan.

Certified financial planner and president of Financial Behavioral Keynote Group, Mary Carlson recommends starting small and building good credit habits over time by borrowing smaller amounts of money. For example, spending on a credit card is typically easier (and takes less time) to pay back than a loan and still builds credit.

If you're a college student, you can apply for a student credit card such as the Capital One Savor Student Cash Rewards Credit Card or the Discover it® Student Cash Back card. The Capital One Savor Student Cash Rewards Credit Card offers 3% cash back on dining, entertainment, popular streaming services, grocery stores and more. With the Discover it Student Cash Back, you can earn 5% cash back on the first $1,500 in purchases in rotating categories each quarter (when you activate), then 1% cash back. Check out Discover's 5% cash-back calendar.

Both cards have no annual fees and no foreign transaction fees, which is perfect for studying abroad. By using these cards responsibly, you can increase your credit score over time.

You can also build credit before turning 18 by becoming an authorized user on a parent or guardian's credit card.

An authorized user is an additional cardholder on someone else's card. While you can make charges on the credit card, you also benefit by piggybacking off the cardholder's credit and good financial habits without even making a purchase.

Carlson says that becoming an authorized user can be beneficial when the primary cardholder has good credit but warns that it can also negatively impact your credit score if the primary cardholder has bad credit habits, such as late or missed payments.

When I began building up savings from working, my first instinct was to deposit my money into a traditional savings account at a brick-and-mortar bank. However, these accounts often offer a measly 0.01% APY, so I'd only be earning a few cents in interest per year.

I quickly learned that a much better option was to put my savings into a high-yield savings account where the money could grow with a significantly higher APY. These days, it's not uncommon to find APYs around 5%. So, if you deposit $1,000 into a high-yield savings account with a 5% APY, for example, you could earn around $50 in interest each year.

Carlson says high-yield savings accounts can be a great option for short-term savings since the money is easily accessible compared to investing in bonds, the stock market, or retirement accounts which is better suited for savings you won't need in the near future.

One option for a high-yield savings account with no fees or minimum deposit requirement is the Marcus by Goldman Sachs High-Yield Online Savings Account. You can read more about our top high-yield savings accounts to find the best fit for you.

When starting to budget, I learned that I need to base my budgeting goals on percentages rather than fixed amounts so that they can fluctuate as my income grows.

The 50-30-20 rule is a popular budgeting method that suggests putting 50% of your paycheck toward needs, 30% toward wants and 20% toward savings. Needs are essentials like rent, utilities, gas and groceries. Wants are the fun things, such as a dinner with friends or a new book you've been eyeing. Savings should be set aside for long-term goals, like buying your first home, and short-term safety nets, like an emergency fund for unexpected expenses.

While the 50-30-20 rule isn't perfect, especially since income typically varies in college based on internships and part-time jobs, it provides a flexible framework that helps keep your spending on track. Plus, if you make more money in the summer, you can adjust the percentages to boost your savings for expenses during the school year.

Learning to stick to a budget can be difficult when juggling academics, extracurriculars and work.

If you don't want to manually sift through bank and credit card statements to track your income and expenses, many budgeting apps link to your accounts and do the work for you.

Monarch allows you to visualize financial goals and personalize your categories to find a system that works best for you. You can create budgets for every category or at a group level.

Another option is Goodbuget which offers a free version and beginner-friendly interface. However, you have to manually input purchases and transactions if you don't have a premium plan.

When it comes to financial advice, it seems like everyone has something to say — from strangers on social media to family and friends. But not all advice is created equal, and it's important to be selective about where you get your information. Just because someone appears to live a flashy lifestyle on TikTok, doesn't mean they are financially savvy.

I focus on finding sources that are credible, unbiased and backed by industry experience. Think certified financial advisors, professors and well-established publications. Once I identify trustworthy experts, I stay informed by subscribing to their newsletters or other alerts they may offer.

At CNBC Select, we work with experts who have specialized knowledge and authority based on relevant training and/or experience. For this story, we interviewed Mary Carlson who is a certified financial planner, president of Financial Behavioral Keynote Group and adjunct professor at the University of Georgia.

At CNBC Select, our mission is to provide our readers with high-quality service journalism and comprehensive consumer advice so they can make informed decisions with their money. Every personal finance article is based on rigorous reporting by our team of expert writers and editors with extensive knowledge of personal finance products. While CNBC Select earns a commission from affiliate partners on many offers and links, we create all our content without input from our commercial team or any outside third parties, and we pride ourselves on our journalistic standards and ethics.

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For rates and fees of the Discover it® Student Cash Back, click here.