If you like to write, you should keep writing. I think it's better to write garbage than nothing at all. The English alphabet has twenty six letters in it. Working together you sometimes get good things, and you sometimes get bad things. Maybe you get bad things more than good things. Maybe some of the things you write have the potential to embarrass you if they fall into the hands of the wrong audience. We live in a society that loves to attack people for being different. Writing is no exception. We have fat shaming and race shaming and politics shaming and belief shaming and beauty shaming and the list goes on and on. If you publish anything, someone (eventually) will try to break it down. But if no one ever tried to string any of the letters together, we'd never have Game of Thrones. You've heard of the saying "United we stand, divided we fall," right? It applies to letters too. Divided letters are just alphabet soup. Does anyone even like alphabet soup?
I've been insecure about my writing. You can't be a person these days and not be insecure about something. Being insecure about writing is easy. As soon as you take a stance or forge an opinion about anything you've invited someone else to weigh in on it. Don't even get me started on "dating" and the judgments that activity seems to elicit. Getting a bad review on Amazon is much better than the rejection one faces when (for example) one likes another person very much and the feelings just simply aren't reciprocated. I think every person knows what this is like to some extent (unfortunately more some than others).
There were brief spats of time when I refused to show my writing to anyone. I held high standards when I should have relished the fact that I have the ability to write well and consistently. I'm a good writer. I can string letters together to make words and then string words together to make sentences. It's a talent people think that everyone has, until you hire someone to make a website and they do great with the coding but spell things wrong all over the place. That's when you know that not everyone can write. We all have our talents. If you're a writer, even a mediocre one, you are already in possession of an uncommon skill whether or not society actually wants to pay you for it.
And no one is going to judge you if you don't show your writing to anyone. Life, however, is pretty meaningless if you don't take any risks. When we write, we are participating in an activity that is intensely private and self-reflective. It's this one thing that's perhaps the greatest magic of writing. The world drops away, and we become both dreamer and crafter. That's worth something isn't it?
Be kind to yourself and write. You can decide to publish later.
Write always. Write often.