Rant about my current job

(18f) I got my first job about 4 months ago and I feel that it’s been somewhat of a rude awakening in a certain aspect. I have known since middle school that I look younger than my age and I would get that I didn’t look my age quite a bit but nothing on the level that I’m getting it now. I’m a cashier and I pretty much get reminded everyday, “oh I thought you were a child”, “you look so young”, “are you old enough to work here?”, “how tall are you”, it also doesn’t help at all that I’m 4’7. I literally had to walk away from the register yesterday to breathe because two customers were telling me I looked like a child, who says that to an 18 year old?!?. My manager also told me I looked 14, and then I had a coworker say she guessed I was 16 (the age limit to work there🙄) and another coworker who asked if I was a sophomore/junior…I’m graduated. I haven’t really thought too much on this until now, when I was in school I wouldn’t get told any of these things. I feel that it’s a factor as to why I can’t make friends and also why guys have never liked me…I mean what guy/person my age would want to go out or be friends with someone that looks 12? I know I shouldn’t care about stuff like this because it’s not supposed to matter and guys aren’t supposed to be important but it is something that I think about and it does make me insecure, especially because there’s a guy im obsessed with at my work. I’m just tired of feeling like shit about myself, I am insecure that I look 12 and it’s been bothering me A LOT. Do any of yall relate? Any advice? (I’ve already been told that looking younger than my age is a good thing, that it will be a good thing in the future. I don’t want to hear this.)