Well would you recommend that I buy a trained bonsai
What is your budget and do you have any idea what a real good trained bonsai costs?
or try to turn an older mallsai into a bonsai?
What we learn on this forum is that this is not going to be a success.
Mallsai are not intended to be starter material, they are a finished, commercial massproduct. There's not much you can do with'm except prune the shoots that grow too long. Turning mallsai into bonsai is done, but it requires knowledge and a lot of time.
As you don't even know what you bought, chances are that, like 99% of the rest, you'll buy the tree, can't wait, repot it, prune it, wire it... and kill it in 2 months.
I recommend to start studying. Don't buy anything yet. Learn what bonsai is, what they look like, how they are grown, and how to get good starter material. Then start looking for such material.