Welcome, Sammy!
We're glad to have you here!
As for your fear of walking for exercise outdoors, I think most of us here have had some not so great experiences. However, don't let it stop you. I have had idiots (almost always men) slow down their car (never on foot - then I could chase the jerks down - lol!) and say stupid things to me about my weight or how I look. Generally they're quick insults yelled, and then they drive away.
Again, even though this is unpleasant, don't let it stop you - these are the EXCEPTION, not the rule. Exercising outdoors is way more fun for me than indoors, especially in the summer. And I am going to do what I need to do for me, regardless of other people I don't know and never will. They mean nothing, I mean everything, so I'll do what needs to be done for me and my health.
If you're not feeling up to outdoors yet (but seriously, don't let your fear stop you - it's totally worth it), maybe do cardio or other exercise videos at home. Lots of people love those.
You can definitely do this, and we're all here to support you while you do.
Again, welcome to the site!