Hit up Vanguard and get some accounts set up.
Put the money away and forget it.
On of the best pieces of advice I can give anyone is never get deep into credit and learn to live on your means. This has two advantages...the main one is you never get lazy thinking you can float money...when you want something beyond your resources you need to step up.
Second, once you have established yourself at a fair wage, any raises you get should be split between paying yourself and paying your retirement. Many say split it 50/50. That way you still get the raise, but you also save more.
It amazing how fast money grows once you build it to critical mass, yet it does nothing when it's below that.