Ideally I would be her first, you won't have to deal with possible unsolved issues from previous relationships. But I don't care if she's been with like 5 people. More than that may put me off a little, since it may seem that she doesn't take relationships too seriously, she's too demanding, or she has something that made all those guys leave.
Probably best that she had a few so that she would have some basis for comparison and not spend her married life wondering if she made the best choice. More than that would be up to her. But 61-300? She might never be satisfied with me!