I say yes, enter. It's important for an emerging painter to begin to enter competitions when he or she reaches a certain level of competency. Participating in this process is an important component in a painter's ability to establish a healthy sense of self as an artist. Having a painting accepted into a prestigious exhibition or selected for inclusion in a book does wonders for the emerging painter's career trajectory.
The painting life is often a solitary one. Without frequent exposure to what's out there, not solely to assess the competition, but also to attain a certain depth of field gained by observation, comparison and appreciation, our perspective begins to narrow. It is only natural; the law of entropy. We are a gregarious species, and even the most reticent among us needs a certain amount of jostling among others in order to be pushed and pulled to our own highest potential. It's kind of like cross pollination. Just as the flower begins to wither and die off in time without the infusion of pollen, so we too, without the enriched experience of new and different energy, begin to grow inward. Even the most creative among us will begin to repeat ourselves without some outside exposure.
One way to get this stimulation is to show up to the competitions. Put your stuff on the line, to either be accepted or rejected. As creative folk, we need to learn to withstand criticism as well as to accept praise with grace and equanimity. The important thing is to keep showing up, work in hand. One way to do this is by entering a juried exhibition appropriate for your level and type of work. It will be a thrill the first time one your paintings is accepted. It will not feel too good if you receive a rejection, but that rejection will propel you to grow deeper and stronger as an artist. Either way, the bar will be raised. You will take your rightful place among your fellows, you will stand up and be counted!