For that level your stats seem alright, just some advice based on my experience through levelling, if you're primarily doing warzones in lowbie from around level 25+ I find it easier to go full madness in dark charge, just skipping the talents associated with lightning charge, I even do well with this in 50 pvp with a decent healer as your dots heal you with parasitism etc, death field is a nice damage boost as well.
Guard swap while in madness (with dark charge) or darkness to the people taking the most damage, in general that's a rule for any tank, if your healer isn't taking any damage and a dps is, guard the dps. Throw taunts out constantly in every spec, even if you're dps, taunts still help the team at no hinderence to you.
For the stats you should be focusing on, shield and absorb are not as effective in PvP as they are in PvE so focus on defense till you hit the diminishing return (about 28-30% I think), if you're serious about being an Assassin tank through to 50 PvP as well then use my profile as a guide http://swtor.askmrrobot.com/characte...d-4bddabccea0d
unfortunately it's not completely BiS for PvP but I'm getting there.
If you do use that as a guide and are wondering why I have points in deception over madness, it's because of the reduced cooldown of force speed (Life saver in huttball) and why I'm using Force-Master gear, I find the set bonus better suited to my needs, as I use to have points in parasitism (before 1.4) it helped with minor self heals and I prefer the color scheme better
Hope this has helped.
P.s. Askmrrobot lie's my defense is at 28% not 24.