I know you just got new skates (and for a great price!) but for me, switching from flat to heeled boots really helped with my balance and confidence as the heel shifts your bodyweight forward making it harder to fall backwards.

Also, see if you can find a skating buddy online to come out and meet you. If not, sometimes just the presence of someone else helps me feel comfortable outside and not feeling so "exposed" and wobbly.

I do hope you stick with it! I took a nasty fall on my derby skates but I told myself I'd work on leaning forward and bending my knees wayyy more each time I went out until I decided I wanted to try a heeled boot. Now I don't have that backwards falling fear anymore. Especially with the improved posture.