You have a good game. I would say a very strong 3.5 or a lower 4.0. If you are serious about playing college tennis, I suggest these things:
1. Lessons once a week with a good coach - you want someone who has played college tennis or better who is also a respected coach.
2. Join a 4.0 USTA team or equivalent internet ladder league. Try to play 1 or 2 competitive matches per weak.
3. Work on all the strokes - your serve looks like it could be very good 4.0 and heading higher. Your groundstrokes look pretty good but can get better quickly with a coach. You need volleys if you want to play college or 4.0+ tennis. Playing lots of doubles and coming in on all short balls will help you learn to volley, 1/2 volley and hit overheads.