Also when you’ve produced a good story and the feedback reflects that, it’s a great ego boost! Always look for constructive criticism. Remember you don’t have to agree with all of it (or indeed any) but if your feedback makes you think “ah I had wondered that” (and this has happened a few times to me) then act on that. It can be confirmation you should trust your instincts when writing and should help sharpen your skills.
Beware of groups (online or otherwise) where cliques seem to develop and be aware there are other writers who will seek to criticize destructively (whether from jealousy or insecurity is hard to say). When seeking and getting feedback you should be able to work out “well has this helped me? Can I use this to improve what I do?”. If the answer is no, ignore! And destructive criticism reflects the person making it, not you.
I find competitions can be a great way to get started on a new tale, knowing that if the stories don't succeed in the competition concerned, I can always rework them and get them out elsewhere. Competitions can vary from those that give a theme to those that give you an opening or closing line but that initial place from which to start/aim for can be a great way to trigger your writing.