That is so great that you are sewing for your kids! I bet they're really excited about it.
Some people sew over pins and some people don't. I don't. You can pin fabric together off to the side, parallel to the stitching line, where they won't be in the way. This works great for straight seams. Even if you leave them in, you won't be sewing over them.
You can pin perpendicular to the stitching line, where the pin crosses the stitching line. This is better if you are going around a curve, where fabric pieces could have more of a chance to shift out of place. Or for quilting, where you have points coming together that need to match. Of course it works great for straight stitching, too. If you do it that way and don't want to sew over the pins, just remove them as they get close to the foot or needle. I have a pin holder right next to my machine, so I can pull them out as I sew.
I don't use as many pins as some people do. I tend to use them as needed. Sometimes that means none or not very many, sometimes that means a lot. It just depends on what I'm sewing. I'm sure you'll develop your own style as you sew. If you're comfortable with what you're doing and it turns out the way you'd like, then that's a good thing! I've noticed with sewing, like many things, there are a lot of different ways to do the same thing that all work. Some ways are just easier or more comfortable for particular people. So, don't feel bad if you do something a different way and you're happy doing it that way.
