Your friends are being complete assholes. Instead of giving you advice on how to better yourself, they call you ugly. Are you overweight? If yes, then try to lose weight by exercising and eating healthy. Does your skin have minor issues? If yes, then try to get rid of them applying various products. Does your current haircut/hairstyle not suit your face? Change it. There are plenty youtube tutorials you can check online.
It's entirely possible that you're just really shy and no one knows you well enough to ask you out. At least, that's what I'm getting from the fact you asked if you were pretty but refused to show a picture of your face. How are we to tell you if you're pretty if we don't know what you look like? Also, get new friends.
Looks like you need some new friends, they sound like assholes. You don't need to be pretty to be asked out. If you truly do have a bad appearance, you can compensate for it with a really good personality.
Older relatives don't count.
Your friends may or may not count either.
Other adults, well... they're unreliable. Also old people have lower standards, it's the reality. Everyone around them is wrinkled and typically fat, so if you're young with fresh skin and in shape, hey you're a 7 at least!
If you want to know, post a pic, and read the range of responses, don't just pick out the ones that confirm what you think. Expect a few 'you're gorgeous' and a few 'you're ugly' no matter what, sift through those for more honest opinions.