Having leveled a primarily protection pally to 70, I would say vs. melee you last forever, but get eaten alive against anything that can cast a half decent spell (even with your auras) unless you focus heavily on spell resist gear.
At your level, I would agree that ret is the best way to go because one of the nicer abilities in that tree is available with only 11 talent points. With the spec I've linked, it should give you some nice damage and keep your mana consumption as efficient as possiable. Use a 2H weapon.
If you like protection, that tree doesn't get one of it's real defining abilities until level 30 (earliest maxed at 34), which is reckoning. The second is Holy Shield at 40.
It's more or less up to you what you want to do, but speaking from experience, I really do wish I start in ret as a pally and respec to protection later, because both leveling and being able to defend myself from stray allies (in my case) would have been a little easier.