I'm a year older than you. I pay for half of everything as well. The difference is that my parents loan me my half at 0% interest and wish to be paid back later (when retired). I take on $13k/yr in debt from them and will end up with about $40k in debt. My goal is to graduate debt free but that's really going out on a limb. Your tuition isn't too bad and you're living at home which cuts out room & board altogether. Just make sure you enjoy the college experience. Get involved, meet lots of people, and have fun.
Here are some things to consider:
-Have you applied for federal financial aid, work-study, scholarships, etc? You may be eligible to work in a lab for work-study funds toward your tuition. If you can do that, then it's a double-win - experience and money! As to getting in the lab/research, hit the ground running. Ask if your professors or TAs are looking for any assistance. Read up on their research and show a genuine interest in their work.
-If you're interested in starting investing right away, it's possible. Open up a Roth IRA. This is a tax-sheltered account especially good for people our ages. Start to learn about investing.
http://jlcollinsnh.com/stock-series/-If going out means going out to bars, restaurants, clubs, etc, then consider getting your own alcohol and just chilling with people in - it's much less expensive. If going out is something you have planned for once per month, make sure you go out AT LEAST once per month. It helps to have fun when you're studying all the time. I find it almost necessary.
-Since you're on here, I assume you know of credit cards and the dangers they can bring. I got a credit card about half a year ago. It's handy. Just make sure you always pay the FULL balance. I think it would be a good idea for you to get one since it builds credit - if you're not taking on any loans then it helps to build credit early. It's not the amount of money either. You can put $10/month on a credit card and it would still build credit! Look for a credit card with rewards, too. I went with Bank of America Cash Rewards. I think it gives you $100 if you spend $500 in 3 months (books!).
-I found that the busier and more involved I was the higher my grades would be. This isn't true for all people, but it works well for me!
A lot of people say I have changed since college...in a good way. College is a time where you can truly be yourself without having stupid high school social expectations hanging over you; use this time to discover who you are. I can't exactly give more details than that but you will see for yourself.