That's awesome! I have a ballet background and I went through the same thing. I was SO weak in my upper body in the beginning, but was able to max the push-ups and get a pull up in about 8 months by doing weight training about 4x/week and working on push-ups and pull-ups almost every day. I also ran 5-6 days week and joined the cross country team to improve my running.
The other people above gave great advice, but the one thing I want to mention is to not let anyone dismiss your participation in rhythmic gymnastics and ballet. Originally I thought I would be at a disadvantage for not doing "traditional sports", but it was actually what made me a unique and solid candidate.
I can't speak as much for rhythmic gymnastics (although I have some friends who do it and I know it's crazy hard), but ballet takes A LOT of physical and interpersonal skills. When you perform in groups, you have to work together to make sure everyone knows the choreography, is doing it at the same time, and that everyone is in the right costume. You have to stay in formation, and you can't have an individualistic mindset.
You also learn to develop a really thick skin and filter the pointless criticism from the constructive. For better or worse, I think most high school coaches would be fired if they treated people the same way that ballet teachers did. After having teachers tell me that I look like spongebob, are fat and lazy, or that I can’t dance so many times, I no longer measure my self-worth off of what other people say.
You learn to persevere through pain. These activities are year-round, so you never get a big break from training. I remember when some teachers would stand right next to my foot when my leg was up during adagio, and I wouldn’t dare give up and lower it to let it hit their face.
Performing teaches you to work with what you have and complete a task even in tough situations. I know people who have performed when they had the stomach flu (or broken bones, etc.), smiling and dancing 110% on stage and then exiting into the the wings to throw up before running on again. You learn how to control your nerves and give it your all because in live performances, there are no redos.
Physically, you really learn how to tune into your body and the awareness you have really helps when beginning other types of movement such as weight training.
Good luck on your application! You have plenty of time to become a beast by the time you take the CFA!