I cant make her horny or affect her in a sexual kind of way! help:(

I’ve been going out with an really amazing, beautifull, cute sweet, kind girl that I found on the internet in an online relationship for about 8 months now and we’ve already met in real life once (where I asked her to marry me :P and she said yes ^^) and im going to see her this summer in about 5 weeks… im 14 years old and she is 15 years old… kinda innocent girl but kinda dirty too ^_^ and me beeing sort of an lil horny joker myself I like that XD but.. well we have had a couple of “ dirty convoes” :P and she tells me that like theyre ideas of what she wil do to me in summer and stuff and im all like O__O! .. and she really affects me.. she makes me soo horny and .. yeah.. crazy!!! insane!! but… she really doesent seem affected by anything of that kind… :( she said “nobody can affect me in that way :P” and .. well me having issues about myself.. beeing a tad overweight.. podgy belly.. huge thighs and stuff like that.. I really blame it on myself :( and im really worrried I cant make her horny and stuff.. but she really is amazing though!! she would do ANYTHING!!! to make me happy!! and thats amazing and I appreciate that a lot!.. but I wish.. it was for her own sake too if you kinda know what I mean :( I want to make HER feel good and .. I want to make her feel like I do about her when it comes to those kinda stuff… she just does it to make me happy and because I want too!.. what should I doo??? will I be able to make her horny if I try something in summer.. like in real life.. or .. will I never be able too??