This sounds vaguely familiar...
After dating a professional knitter for nearly 2 years, I decided at the age of 52 to learn how myself. (There's a whole story to go along with that, but I won't get into it.) I had the advantage of learning from a regular Jedi Master of Yarn (seriously, she's amazing) and knowing that I probably couldn't get myself into more trouble than she could get me out of (knitting, at least). My first project seemed simple enough, but in retrospect it probably wasn't the best choice for a first-timer. I was -- literally -- learning how to increase from the first knit stitch. I learned increases and decreases before I learned how to cast on (beyond a slip knot that is). It wasn't a great way to start.
So in addition to the sage advice already offered here about big, light colored yarn and big needles that aren't metal (something ELSE I had to learn the hard way) I would say:
(1) Be prepared to do a lot of stuff wrong in the beginning.
(2) Don't be afraid to pull it out and start over.
(3) It's knitting, not rocket science. (That was a hard one for me!)
(4) Yarn is not(!) a material that lends itself to close tolerance work. It stretches, bends, frizzes and splits and can seem downright spiteful at times. Don't take it personally.
(5) Probably the most important mantra you can learn is "trust the process". Because when you start something, you probably won't be able to see that it's doing what you want it to do until you get further along. So you have to trust that what you're doing will give you the result you're after, even if it doesn't look like it on the first row.
(6) Breathe. No, seriously! I can't tell you how many times I caught myself holding my breath. In fact, I didn't even realize I was doing it at first. But when I started learning k2tog it took me so long to get the first 2 (absurdly tight) stitches knit together that when I (finally) exhaled I got a bit of a head rush from the sudden restoration of oxygen to my brain.
(7) Even the experts do stuff wrong. You will too. And it's okay.
And finally... welcome to the dark side. (bwahahahaaa) You'll love it here. We have cookies.