It’s young age, everyone would want to enjoy as long as there is no “extra activities” involved. Once in a while should be okay but if it is a regular thing, you can have a genuine talk with her and even after that it doesn’t stop, simply it is disrespectful for the relationship and ultimately she is looking for attention! 

It’s similar when girls say “I don’t want attention but I am just posting for myself” don’t listen to it. 

You guys are still in early 20s so if it doesn’t fit, move on. Don’t settle for such behavior!