Hi I was wondering just how much time investment it would take to learn the basics, and compete at mid levels

Ive played SC1 but not online etc..Ive also done WC3 melee games but I can tell SC2 is a lot macro intense. Any pointers are greatly apperciated

Terran really interests me as well as zerg

Sc2 is a great game, but by mid-levels, do you mean gold-plat leagues? Because that doesn't take that long if you keep laddering.

Not exactly sure how the ranking system works, but I just want to be in a casual ranking system where im not competing with try hards

Well, the system works by trying to pair you up with people the same level as you. Most of the time you play people slightly below/slightly higher/similar to you.

But if you don't care about what league you're in, you can still have fun, try out new stuff, or do whatever you want in these matches.

hm okay cool, I think ill try this out d3 is boring me out of my mind

lol if you could stomach d3 for more than a month you will love sc2

start with protoss..

Yep, definitely start with protoss.

You'll do great.

Learn Terran first. It's by far the hardest race to play, so when you decide to switch to Z/P they will be ezpz.

Play Protoss if you want a challenge
Zerg if you want to fall asleep in game and wake up to a win