First off... Welcome to Pathfinder!
I'd seriously advise you
against trying to start with a stat of 18. It's arguably because of my personal tastes... But I've never liked having a character that was horrible or mediocre at most things and insanely good in one. Pathfinder Society still caps level at 12th if I remember correctly, so even if you wanted to play a caster, a 16 in your casting ability is the highest you'd need to cast all the spells that will ever become available to you. I personally think that those points can be more wisely spent by spreading them around a bit.
Paladins can tank in Pathfinder, but they don't start with
any healing. Even in later levels, paladin healing is less effective than that of a dedicated healer. The big reason that you'd play a paladin is to fight evil critters--they have abilities that optimize them against evil targets.
Based on what you've been talking about up-thread, I might suggest that you give a look at a melee-focused cleric. If you want to tank and heal, clerics can actually tank rather well. It'd certainly be a "defender like class with self healing," although you'd have to make some specific choices to get the damage output up.
For a cleric, I'd get your Strength and Wisdom scores to at least 14 each through the point buy, and then select a race that gives you a Wisdom bonus (dwarf) or a floating +2 bonus (human, half-elf, half-orc) and use it to bump Wisdom. I'd also make sure that your Charisma is at least 13--your channel energy ability is based on Charisma. A 14 would be nice, but not critical. You only have to spend a single feat to gain heavy armor proficiency, and besides, you
want to be able to melee well as a cleric. The vast majority of healing is accomplished by touch spells, so you're going to have to wade into the thick of things to heal your pals. If you pick up the Selective Channeling feat at first level, you can do some at-range healing for your friends without also healing your enemies.
At 1st level, you're basically going to do melee and heal. Stick by the fighters (or whoever else is on the front line), beat the bad guys, and heal your friends. Chances are that you'll need your spells to heal your buddies, but
bless is a solid choice (grants your allies an attack bonus).
Command can be handy in certain situations.
Doom is basically a debuff you use on the boss, it gives them a shaken condition that makes almost anything they do less effective.
Where the cleric really starts to shine is at 3rd level, when you start getting some awesome clerical spells.
Aid gives you attack bonuses and temporary hit points, whereas
spiritual weapon basically gives you a free extra attack every round. I'd definitely take both of those spells.
Sound burst can stun enemies, and
augury can give you helpful hints when you've got an important choice to make. You also start getting spells that can buff abilities at this point.
The cleric only gets sweeter from there if you want to tank and heal effectively.