My 3 1/2 yr. old made some serious allegations....What should I do?

Last night I was giving my 2 lil ones a bath when my 3 1/2 yr. old told me she had a "BOYFRIEND". I told her that lil girls didn't have boyfriends.....She then told me her boyfriend was "V" who is the sitters god-son. I thought it was wierd so I started to ask her what she did with her boyfriend, I also asked her if her boyfriend touched her......she said "YES" I asked if he touched her in her private and she said "YES" and on her "BUBIES" I freaked out and called my mom and my mother-in-law, I also talked to the sitter and she asured me that the girls are never left alone or unatended, and I know the sitter loves my kids and my kids love her, and her family.....Should I jump to conclusions or should I talk to her more. I'm taking my baby to the Pediatrician so she can get checked today. I'm soooo worried, about her. I myself was molested by my sitters son, when I was about 6 yrs old.