Find the races. Go to the races. Meet people.
See what your college offers. Lots of colleges have spare/trial bikes. Not great, but OK - sometimes. I was involved getting those going at my kid's college.
Descents and flats are more about your body position (aero) which is much more significant than the bike. If you have a bike that can climb fine now, sounds like a good bike.
Save your money till you know more.