Was that a deal breaker???

Not long ago i met a girl who was very attracted to me - she wanted my number and started texting me, we started dating for a month - everything great. Im lacking experience with girls, so I was not very aggressive during that time (never made a move on her sexually, but i kissed her, held hands, made out regularly). So she texted 2 mutual friends and asked behind my back if i ever had a girlfriend. He refused to reply but told me. I was kinda irritated since she didnt ask me in person, so i texted her 'next time you want to ask me/know something about me, ask me in person not via other people'. (I regret that since it would be much much better to tell her in person).

Next day (date) i brought it up and told her i m not mad at her but dont like things like that. So i told her she can ask me now. She did and i told her i have never had a serious relationship - im 25, and that i have never had feelings for any girl i have been sexual with. She was quiet after that and then i told her i have never had a gf because i was too busy (which is true plus i have never met any one special) because i was studying plus i was athlete. From then on, i felt everything was different - she didnt text me as often as before and i just felt something is not the way it was - she was distant.

So 2 weeks later she texted me AFTER the date (she gave me just one kiss after and left quickly - normally we made out after a date), that she is not ready for somethings serious. I found out she tried to get back with her ex - happened to me again (they were together 4 years and she left him because he was neglecting/ignoring/cheating her and was a 'bad boy' 6 months ago). So im wondering was my inexperience a deal breaker for her in your opinion and that was the reason she missed her ex and try to get back with him. She was very very into me/eager to see me (texting good night everyday, telling me she cant wait to see me, asking me if im falling in love...) before that topic about my past experiences came up. Im often too honest but i would lie if i could about that, but since we have some mutual friends from before that was not an option.