I was thinking of starting a pure mage but didn't think it would be any fun. I started once but then stopped at like level 12 because I dint really like it. And will it be good to start on Master and any good ways to level up destruction fast. Anything will be aprreciated

It becomes more fun at later levels. In the beginning it's pretty tiresome IMO.

As for leveling destruction fast, go to Winterhold, join the College and train with Faralda. Personally I can easily amass some 30,000 gold by level 12 so using trainers has been worthwhile for me.

Hmmm I still don't know, maybe after this playthrough I will consider playing as a pure mage on master difficulty.