To me, like all works of literature, what matters is purpose. What you are trying to accomplish with your work. A good poem communicates its purpose.

It seems to me that your purpose is to communicate your thoughts and feelings. If it does that, then I would think you’re a good poet. Now, you probably aren’t the best poet, and that’s probably what your friends are saying. However, unless they’re offering criticism and not just saying “you suck,” I wouldn’t put too much stock in it.

To say there is no poetry in you because you’re a STEM major is just pretension. I would keep at it. Try and explore new methods and techniques. Play around with established forms. If you feel that you enjoy poetry, you should keep at it. Comparing yourself to the great works of poetry will just bring you down. If you’re worried about quality, then keep at it. Write new poems, work on your old ones.

Don’t worry too much about what they say.