I have a great deal of experienced with critiques for both my writing and for my public speaking.
Public speaking - I recommend "Toastmasters" Critiques are 90% positive feedback with a suggestion or two of what you could do to improve. There are clubs all over the world, and there are probably several close to where you live. Dues are reasonable (about $100 a year.) You can go to a meeting as a guest, and see if the group feel like a safe place to try speaking. The world is full of all kinds of people, and, while it's possible to get a mean spirited critique, it's highly unlikely. As a guest, you can listen to other people speaking, and hear how people evaluate their speeches. And you can make friends there. As you probably know, public speaking is the number one fear for most people. (Death is number four.)
Writing - I belong to two writers' groups, and I love both of them. In both groups, we give each other encouragement and positive feedback. in both groups, we can ask for the kind of feedback we want. When we're starting out, or writing a first draft, all we want is encouragement to keep going. We don't need criticism. If we have a finished piece and want to enter it into a contest, or try to get it published, then we usually want more thoughtful feedback, and more ways to make the piece better - as good as we can possibly make it.
In one of my groups, a retired teacher was leading the group. She was trying to teach us something, and two of the members weren't getting it. I was uncomfortable with the conversations. One of the members walked out and never came back. The next meeting I gathered my courage (I'm not good at confrontation.) and suggested that we only give positive feedback unless the writer specifically asks for something else. It worked well, and we haven't had hurt feelings since then. If the idea of a writers' group appeals to you, you could check out a group in your area and see if it feels like a comfortable place to share your work. The public library is a good place to start looking for a writers' group.
If you take a class, either a writing class or a public speaking class, be prepared for more criticism than you'd get in an informal group. A class is meant to make your work better, and that means more - gulp - criticism.
If you're serious about writing, I suggest you take the risk and give a writers' group or Toastmasters a try. It's a risk, of course, but, if this is something you really want to do, it's worth it. Besides, it's much more fun to write, if you have someone to read your work to.
Elaine Glimme - author - "Temporary Address" and "The Molly Chronicles"