Congratulations! How exciting to get that acceptance letter.
If you weren't motivated after high school then waiting to go to college was the best decision you could have made. I forced myself through undergrad not knowing what I really wanted to do (but feeling that I had to go) and graduated with a degree that I got minimal use out of. Since then I've completely changed fields/interests and have gone back to school to pursue them. It has worked out, but if I could go back I would have waited until I was excited about school and a little more focused to go to undergrad.
Best of luck to you! I hope you absolutely love it. Are you leaning toward any particular field?