Skin of vagina is very loose
Answer:No, it doesn't necessarily mean that she has had a lot of intercourse. Every woman's vagina might differ in some way or the other unlike porn, where they all look the same. If her vaginal walls are too loose, she could also practice kegel exercises to tighten the muscles.
Learn to trust and respect your girlfriend despite how you think her genitals might look. If you suspect her of cheating on you, have an honest conversation with her and if you're still unable to trust her, it is time to step back and deal with your own trust issues.