<prompt> Human: Hi yall. Hopefully you guys can help me out. Im 17 years old. For my birthday a few months back I asked my parents to help me set up a bank account, and I walked out of the bank with a debit card and a credit card as well. Not long after that, I got my first real job and took a brief personal finance class, but overall im still baffled. What I knowhave:- Currently have 600 in bank account, 5050 split between checking and savings 25 automatically into savings from checking once a month- Should have close to 2k in account by end of summer due to job. Dont have a job lined up for the school year but I will be working the summer after that at the same place before my freshman year of college. Will be adding 75mo during the school year even if no job. - CC is a Visa, dad is cosigner not sure what its called, limit is 7.9k, rate is 18.99 though I think it is down to 18.74- Know basics of finance from class; things like Rule of 72, pay yourself first, how to make a budget and balance a checkbook things I admittedly do not have to do often, how a CC works, some types of investments, basic things people should know. Things that I wantam trying to accomplish:- Building credit. Thanks to parents good credit my CC limit is enormous, but very soon I will be needing student loans, and my parents told me a high credit score will help with that. They also told me to use my CC and pay off the bill in full as soon as it comes, but from browsing here I am confused as to whether this is bad or not. I do not use much of my credit - then again, no 17yo should have access to this much credit IMO. I am considering buying a 3DS later this summer, so I am not sure if I should use my CC and pay it off over the next few months or if I should pay it all outright or use debitcash instead. - Invest! We did an exercise in the finance class comparing 2 people who both invested - 1 for 10yrs and then stopped, and 1 who started 5yrs later than 1 and invested for like 35yrs. I was surprised that person 1 ended up being much richer, and was like, Hey, I want to be that person! I know of a few types of investments I will have to dig up my textbook when I get home, but I do not know how to start or what to do, really. All I knowbelieve is that by starting early, I am setting myself up for success later on in life!  <response>: For the credit card - pay it off in full every month. People who tell you that carrying a small balance will help your credit are confused. Dont buy anything you couldnt pay cash for and treat that cash as spent once the charge is on your card.For investing - if you need the money youre saving for college, its not enough moneytime to both doing much beyond keeping it in savings, given current interest rates. If it is available to invest for the long-term, open a Roth IRA with Vanguard and put it in the Target Retirement 2060 fund VTTSX. I opened my Roth IRA when I was in high school and having started retirement savings before college really helped me get on the right track as soon as I started working as an adult. 