Even training against a Bjjer is good for learning how to escape from under someone larger than you, maybe even better since a Bjjer will know how to keep you in that position and apply top pressure. A side mount is a side mount whether you're doing sport or self defense. The only thing missing from sport practice would be the striking component. However, if you're really good at escaping positions, you can really learn strike defense in your spare time. The main thing is learning how to escape those positions, which a sport school can teach just as well as a school based in self defense.
Again, I can personally attest to how good women become at Bjj escapes after just a few months of practice. The fact that they tend to be smaller forces them to be more agile and be better at escapes and counters, whereas larger males tend to stand their ground and push back, trying to establish top position, and be more aggressive.
I think you as an Aikidoka would appreciate that.
Personally as a larger male, I always envied the smaller practitioner. I really think they end up being better in the art in the long run.
), but in most styles a starting focus on self-defense usually leads to teaching a few simple, repeatable techniques that wouldn't come into play against a skilled opponent, because they wouldn't commit the common errors. So, I can teach a student how to off-balance an average person who has them down pretty quickly, but that same technique won't work on someone with a year (or probably less) BJJ, because they'll avoid giving the positions an untrained person would give. I'd expect what works on a BJJ person to mostly work on untrained people, but will take more learning. That's the primary advantage at the beginning of an instructor taking a self-defense approach to the art - any art. After a year or so (at the most), I'd expect SD-oriented BJJ looks a lot like good sport-oriented BJJ, if both are true to the full curriculum.
Do not know if you are still around or got your answer?? Some people here have given good practical advice and suggestions. I would not repeat what is said, only it sound to me that you maybe feel your confidence overall has taken a knock from this? I imagine this can only be made worse that the person who did this on you was or is a friend. This could feel like a sort of double blow maybe. I know people this can cause them to question their selves at some levels. You have supportive friends there with you?? You know I think you are brave and I think you are awesome to post this here, because you know there are always other girls in similar situations that wonder oh goodness what do I do now to stop this happening. Thank you for posting. I do not have much to add only there are lot of ways for you to gain back the confidence that is yours as a young woman that you deserve to have and to keep for always. Physical training of any kind will help yes, does not have even to be fancy martial arts to make you in some way unhurtable, can be just doing a little fitness routine or do a few little things in your college gym or a dance class or jogging or whatever, and but mostly I would just want to urge you to take this incident in context of your life as an entirety and not allow it to define anything too much about you. Please let us know how you get on and what you make of it all and what you decide. ANd anyway, you are not just somehumanperson, you are awesomehumanperson 
