Some have suggested that you can learn just about everything you have to know to play melodies on a harmonica in about 10 hours of actual playing time. After the 10 hours your skills advance very slowly. Possibly your tone and expression improve a little. And your breathing rhythm also gets much better. But for all practical purposes others around you can't tell much difference between you and a more experienced player.
I have heard the statement, "The only difference between the harmonica player who has played 10 hours and the one who has played 10 years is the number of songs they have memorized."
You have probably passed the 10 hour mark by now. If so, consider yourself as having arrived at the master level of skill. From here on out it is just a matter of adding to the number of songs you have memorized.
That joy that you experienced when you first heard yourself playing recognizable songs may soon grow weak. Learning new songs will renew the joy. Also, there are advanced skills that you can work on. You can begin to learn to play in the crossharp position. Or you may want to move up to the chromatic harmonica.
California, Here I Come