Please help a starting mage :)

Ok so i was in a battleground and out of no where a mage by the name of Iceicebebe 2 shots me with frostbolt. Afterwards i looked him up in the armory and his spell power was 260. Also i had medium / high health at the time for the level. Here is what i need help with. 1. Was it his spell power that did the damage to me or something else? 2. If it was spell power how did he get so much of it at a low level? Please help me this is my first mage and i want to play him well. The link to his character is here

http://us.battle.net/wow/en/character/caelestrasz/Iceicebebe/advanced
He has full BoAs- they give you very good stats.

Basically- he had better gear than you.
Two crits would've taken out just a bit over your max health.