One of the farmers here has a half dozen to a dozen loquat trees growing. He keeps them about 5 to 6 feet apart and they are about the same height.

They do seem to be slower growing and slower to fruit than his mangoes or his papayas. Hope this helps.

That does help, Daai, so much. It's precisely the type of input I needed.

Now that one of the plants is growing, I've realized that I need to do something with the other ones. Someone told me in the past to space them, but since they were so so small, I figured I didn't need to do it right away. But now that one of them is getting large, I feel more inclined to do what I could have done before. I also have a fig tree, which produces fruit and it was quite slow growing at the beginning, but is finally picking up and growing more in height and width. That plant isn't surrounded by any others and I had been comparing it to the loquat trees and wondering if they are similar in that they seem to be slow to grow/produce fruit.

Loquats here in New Orleans grow to 12 foot tall or a bit more in full sun (about as wide) and waaaaaay taller in full shade (but then its a tall slender tree without much spread). You will get fruit in both cases but more so in f/sun.
Growth is relative ya know ;o) Compared to other fruit trees I'd say its faster apples and such. If constrained your growth is much slower.
Very pretty tree even if you get zero fruit.
Very few fruiting trees, especially seed started ones, will fruit with the first several years.
Mike