You can summer prune to help keep the tree at the size that you desire. Pruning will keep help build a stronger framework as long lanky limbs may break from the weight of the fruit. Lots of information online on how to prune plum trees. Here's a decent one from Stark Brothers:

https://www.starkbros.com/growing-guide/how-to-grow/fruit-trees/plum-trees/pruning

Best of luck!

Thanks Jason. I'll cut the long branches back some.

You might want to be easy on pruning ...you might have Deer doing it for you lol.

Konrad, I haven't seen evidence of them in the yard. It's all open field around me and I always thought prey species won't cross without coverage escape near. So they would trace along wood lots etc. I see them running across fields.....to get to a safe space, partly.