I really want to start online business BUT I'don't know what to do and I'm NOT good at anything. what can I do?

Based on your question, I think you're not yet ready to start an online business. I will leave my own thoughts and you think about it.

Since you said you are not good with anything relating to an online business, then starting one upfront will be a disaster.

The best thing you can do is to pause and learn, practice while you learn, get someone who is a step above you to keep you in check (a mentor) and as well you can ask the person some things about the business.

There are three approach of learning to start an online business

You can join a startup group that wants to venture into an online business

You can start on you own but with guidelines from people who has done that business model or related business model

You can lean in towards what you know and make it an online business

While doing this thing, on your own you will discover the niche you want to venture into, you will discover the right steps to take and structure the business well right from the onset and you will also be able to held accountable which is a vital trigger for starting an online business.

Don't rush to start an online business now since you don't know anything about online business, it is not as easy as you may see it where you will pick a niche and do marketing.

There are other things involved which you need to know before you start. My thoughts should help you if you go through it and make it a guide for yourself.