Which frame is better for me?

I have the option between a
S&M ccr frame 21’ for £300
Or a
S&M black magic frame 21.5’ for £350
Or a S&M ccr junior 20.5 £300 which I worry for a trail bmx will be too small for me
The frame is for a trail bmx and I am 5,6(growing)
The problem is that the guy selling the ccr is not replying to my messages.
I was really excited about buying the ccr but I’m not sure if the person will reply.
Will the 21.5 black magic be way to big for me or will the ccr junior 20.5 be too small for me.
Thanks