I am a 21 year old male and I have had sex with ~20 girls. When I was with my ex (together for 8 months) she did not like the fact that I had slept with so many girls.
I think the main reason I tried so hard to sleep with girls up until a year ago was because I had low self-esteem. I was always shy when I was younger and did not get a lot of female attention, I sought validation from these one night stands.
Nowadays I get female attention and I don't try to sleep with every single girl (90% of the time).
Some times I tell people I have only slept with ~15 girls because I don't want people to be put off.
That would be assuming that he's been having sex with women since he came out of the womb. He has not. Assuming it's only been since he's been 16 or so, that works out to be about 5 a year. That is certainly on the high end.
To the OP: I'm sorry that you had low self-esteem. Compounding it with lying isn't going to help. Just tell the truth and if she doesn't want to date you because of it, then that's fine. People can choose not to date you for any reason at all, from the color of your eyes to your weight to the number of people you've slept with. It's okay for people to find that fact important and if they don't want to be in a relationship with you because of it, then it's better if they find out early.