Can you change out a bike seat? This seat on my bike is really narrow and uncomfortable. Honestly my old bike from when I was 10 is better, but because they're different brand bikes, can I switch them?

I changed my seat out when my bike was brand new. I don't know what the manufacturers think when they put those skinny and hard seats on a bike. They are anything but comfortable. I bought a nice gel seat. It's a little wider and sooooooo comfortable.

As long as they are the same size you can. Most bikes have universal sized seats and will interchange. Except for some of the newer high dollar bikes. As long as the shaft is the same, it'll work.