At that level it doesnt make any noticable difference i guess. Anything you do will be enough to compete in pve. But traditionally, more health is always better for a tank. You have a skill called sun shield in aedric spear skill line that scales from health and morphed into blazing shield. You'll able to unlock that around level 30. Very good skill for pve tanking but not worthy enough for pvp, due to the restrictions came with recent updates.

Heavy armor dps builds are doable if you have a lot of champion points, but it is not optimal. Considering you have no cp yet, you should stick with tanking if you want to wear heavy armor.

You can also make a heal-tank build, investing into magicka with heavy armor when you advance your level a bit. Check tamrielfoundry.com for build options. Those builds are mostly for end game but at least you can get some ideas from there.