Help with insecurity..?

Hi guys, I am real insecure about my body. I'm 19 yr old male about 269..yep I'm a chubby lol. But anyways i just feel like females don't like big dudes. Im tallking to this gurl currently and i feel like were on a smooth path and everything is going right. But tonight she asked how big my dick was. Okay so I told her and it went down hill from that. She didn't make fun and she still has the same feeling for me and cares about me..i was just confused on why ask the question knowing the size of me. I wanna lose weight and have been trying to cut back on a lot of food and drinks..but I just really like to eat lol. But I wondering YA how can i get over my insecurity? Thanks