I'm here again lol

I've been getting into art more as a way to escape from all of the exams and time spent studying in the real world, and I think I've improved a ton and am considering openeing an art shop. Examples are below as are the pieces sale price at auction for reference.

Examples (Click for full size)

By far the piece I'm most proud of is this one. I spent about 5 hours from cutting to finishing touches and it sold at auction for 160k.

This one is also one I'm pretty proud of. It sold for 200k.

Those are the two examples that best show my current ability. What tier should I be in?