You can wear any armor type you'd like. If you don't want to wear heavy armor then simply don't.

Costumes can also be your friend. At early levels you have to mix and match armor out of necessity and it can make for a pretty strange looking character.

I'm lvl 7...i don't even know what I'm doing..but I am happy about the staff:)

Now you have the ability to equip a second weapon which also opens up another bar of skills. I would recommend a restoration staff on the back bar for survivability/heals or another destro staff if you are using a pet build which require the skills on both bars.
Stick with it though. I've mained a Sorc since launch and absolutely love the class. The game doesn't really begin till lvl 50 honestly. At that point youll have access to all skills and abilities to play around with a multitude of different builds, whether it be magicka or stamina.
Don't worry too much about builds or rotation while leveling, just play around with different skills, by the time you're lvl 50 you should have a good idea of which skills are more useful than others. Just make sure you have at least 1 skill from each of the 3 class lines. That ensures each line will be leveled at about the same pace. MagSorc is currently the FOTM (flavor of the month) and they are pretty devastating in both PVE and PVP, but that was definitely not always the case.

Collect items for making your own Read the books lying around the crafting stations.