Congratulations! Hopefully someone got some video of your last shot or two? You can always go back and watch it and give yourself some inspiration if you're in a slump.
I just looked back at my records. I hadn't been bowling quite as long as you before my first, but not by much. It was 4 more years before my next, but then I had a few in the next couple of years. Of course, that was when I started getting coaching. Like other said, now that you know you can do it, there will be a bit less pressure the next time you have a big string going.