My daughter is a distance track athlete and she focused on D1 schools that she wanted to go to in her ROTC application and got selected for her top 3. However, once she started talking to the D1 coaches, she got a sense that D1 athletics and ROTC would not play very well together. As others have mentioned, as a distance runner, you never get a break as you are doing XC, indoor and outdoor seasons and still running all summer to stay in good shape for the upcoming XC season. So, what happened with my daughter is that she started considering other options and landed at a D3 school and it has been a great fit (this required a transfer, of course). She is the type that is involved in everything under the sun. In addition to ROTC and 3 varsity sports, she is in student government, a sorority, TA and works as a waitress on her lighter class day and when she can on weekends and holidays. So, she might have been able to balance ROTC, school and D1 sports if that was all she did but she wanted to get a broad college experience that went beyond that which is why she didn't go very far in pursuing a service academy option.
Whatever the case, make sure to have frank talks with both the coaches and ROTC about what their expectations are and what takes priority. With good information, you are better equipped to make the right decision for you.