My service dates were 1967-1969, is it too late to go back to school?

If you are VA rated with a disability you may rate free or drastically reduced tuition in many states. If that is applicable to you, I would check with my state.

15-year time limitation for using Post-9/11 GI Bill benefits.

I'm not speaking with authority here, but I thought the education benefit had to be used 15 years after separation or to similar effect.