I think it's a good idea. Plus, if you can play multiple positions, I think it really helps you understand yourself as a pitcher better, you can see the perspective of your fielders and see how your pitching or your decisions on the mound can effect them.
Plus, first base is the most fun position in the field in my opinion. I played a little 3rd and outfield, as well as pitching, but I primarily played first, it was just so much fun.
If you ever want some help with stuff defensively at first let me know, I did pitch, but I was a first baseman through and through, and I still play first base whenever I get the chance to play in an alumni game, a softball game or whatever baseball variant it may be.
I played a lot of right field as well, so feel free to ask for advice there if you need it too.