Age is just a number. It doesn't matter if people say you are too young to achieve something or too old to learn something, just don't believe them.
Beauty Standards Set By Society
The fair may not be lovely and slim may not be fit. Every individual is different so accept the differences and don't compare yourself to false standards of beauty that the society has imposed on you.
People who don't care about you
You think you should give more to attract more attention but those people have just taken you for granted. The more you care, the more they take you for granted. Start ignoring them and focus on yourself. You need to be your first priority.
What others think
No matter what you do, someone somewhere will be disappointed in you. You can never make everyone like you. Just do your best and don't bother what people think.
Your Past
Don't let yesterday disturb your today to spoil your tomorrow. Your past does shape you a lot but you don't have to carry the baggage around everywhere.
Toxic people
No matter how good things are they always manage to find something bad in them. Being around such people may make you negative about life and will drain out the positivity in you like a parasite.
There are no fixed standards for success and there will always be someone more successful than you. Do not define your success with the money you earn or how the world tells you to. Create your own story.