At 199 grams, your snake is obviously still young and should be growing rapidly. A general rule to follow is to feed about 10-15% of the snake's weight at each feeding. That would be 20-30 grams of food. How much do the mice weigh? Assuming they are adult mice, they should be 20-29 grams each (according to rodentpro, but depending on where you got them it could be quite a bit off from that).

1 mouse is probably good for now, but your snake may be big enough to take 2 mice per feeding before you run out of those 10 mice.

A rat pup is about the same size as an adult mouse (again according to rodentpro), so by the time the mice are gone, you will probably want the next size up. Check to be sure based on where you are getting your feeders, because the names of the difference sizes of feeders can be quite different depending on where you get it.