Your level is fine if you are able to handle things. Where you will probably run into problems feeling underlevel is after Dragonspyre. Getting through Dragonspyre in your mid lvl40's is pretty easy, but then there's a leap in difficulty to Celestia. Your level is just fine for where you are. If you start struggling with a world, take a break and go do Grizzleheim/Wintertusk and level up a little and get some better gear. Most important thing is have fun.
Hey Guys I'm a lvl 38 pyromancer and only have 1,851 health based on my friends I think that's low but I have completed most of Mooshu no problem so I don't know can you guys help me?
Help you with what? Your life is lower than some other schools because Fire and Storm have the strongest base spells with the lowest life. If you're playing fine without getting clobbered you don't need help.