If you have an idea for a doujinshi, go for it!
You certainly are quite good artist already, some proportions might be a bit off, but overall, I like the style you have.

The doujinshi doesn't even have to be long, so you won't feel exhausted over the massive story and effort you have to put to it.

And maybe after some years after you've gotten even better at drawing, you might want to redraw your doujinshi, who knows? :)