My partner keeps asking if we could do it even though I keep saying no.

Hi, so basically my gf (19f) keeps asking to have sex and I (18m) keep saying no and yet she still keeps asking and gets all emotional and upset. The reason that I’ve told her is that I don’t feel like doing it, however the real reason is that I’m really bothered that she’s not a virgin but I am. She lost her virginity to another virgin and to me that’s very special to have your first with each other so the emotion and excitement of that first time will never be replicated. Some stranger will be thinking of her as his first time.

Tbh I also feel like jealous that she lost her virginity when she was 16 and I’m already 18 and I can’t stand the thought of her loving someone or some guy touching her so lovingly. Some thoughts I have are like if she felt so good and in love with the other guy why not go back to him? Like I’m just a replacement and she will never love me more than her past.

Is it just me, how can I get over it or at most any tips to stop her from asking and getting frustrated?