Talking with an older man makes me feel young

I feel so old and gross being 18 and not amounting to the stereotype of a girl. All I wanted was to be a girl since I AM a girl. But I just don’t have the cliché feminine/youthful traits like being petite (I’m XXS but unfortunately I’m not short), bigger and laterally wider eyes, small nose, etc..etc…I could care less about curves or my chest. I do not feel comfortable or secure. So here I am talking to a guy who’s mid aged and I genuinely feel like my age??? I don’t know why