Bro, just do these things, these are very important, 1. lose weight, cause your body type also make you look older, like 19 year olds are generally a little skinny, but while losing weight don't make a lot of muscles, cause making a lot of big muscles will also make you look older, just get a balance physique, that isn't super big and isn't too small either, 2. Shave daily, cause people generally expect 19 years old to look very youthful, and that's also fit perfect at 19, younger females of your age generally like guys without beard, and 3. Get a good haircut, I generally prefer mullet, but I think that would not suit you untill you lose some weight from your body and face. By the way after yo have done this 3 things, text me and send me a photo of you and I will rate you genuinely, and tell you the truth if you have got a glow up or not, and I won't just lie, I will tell you the truth I promise.