When you go to choose glasses for the first time, you should choose frames that makes you comfortable and looks good on you. If you feel that the frame looks good on you, you will feel more confident with them on.
Don't care about how other people think you. AS long as they look good on you and they are comfortable to wear, you will prefer to wear them all the time. So when choosing glasses for the first time, make sure they fit your personality, like face shape and skin color.
Just think you are wearing some beautiful accessories. It is quite common to wear glasses and people will not pay much attention to your glasses. Stand in front of the mirror and say to yourself "you are the most beautiful".
The important part of wearing glasses for the first time is carrying yourself with confidence. The way you do it is to pick out frames that look good on you and you feel comfortable wearing and once you have these two things the confidence will follow and you will be able to own your new look. As long as you pick out glasses that look good on you, you won't look ugly and nobody is going to laugh at you, they will comment on your glasses, but they won't laugh.