Look the answer is no you shouldn't but of course you should

Even if you both agree not to discuss the past which is very difficult , if you meet someone later who new her back then and they say something like "ooh man you should have seen her in college " it's going to grind on you all over again.

Our past helps shape us , good or bad.

I mean has she cheated on anyone before , did she use protection before , what's her stance on abortion .... All things you should know and she should know about you and unfortunately sexual history is one of them.

Now this doesn't have to be a one hit conversation but as you date certainly things you should understand.