You shouldn't give up writing, but you should give up expectations of being acclaimed as a good composer any time soon.
If you are a good composer, that may be later, after years of working on things, informing yourself, practical experience, and maybe a lucky break. If you love music, you will want to go on writing, and it will be its own reward.
If I were you, I would look at what you want to achieve and form a plan, a project over the years, for you to achieve it. In the meantime, don't post for others' criticism, as it will only put you off, and how over the internet will you be able to distinguish 'good' criticism that helps you to do better from criticism that might have you haring in the wrong direction?
Someone you actually know in real life, that you respect as regards music, can help you to 'improve your game'; friends and family can give you encouragement, especially if you compose for an occasion - background music to a play, a local concert etc.
I spent several years of my life writing historical novels and got nowhere, but I don't regret it. The experience was joyful, like a sort of mysticism, and my husband and I hugely enjoyed the research. One day I mean to go back to it.
But in the meantime - not writing it, but playing and listening - it's all music, music, music...
