it's never too late. though you should still put in your two weeks notice to your current employer when the time comes. but, you should not quit until you have another job lined up. search for jobs now outside of normal working hours, and tell them you're looking for other opportunities.
some companies will ask for available start dates, and you can put two weeks from current job, next month, whenever. most places you can also say to not contact your current work about you leaving. though it's usually only to confirm your employment and pay history. but you can never know for sure.
if you get interviews with other companies, they will likely ask you why you want to leave your current job. then it's up to you how you want to answer.
have you talked to your current employer about other opportunities within the company itself? assuming you're doing good work at your current positions, most employers will consider in house people first before outsiders since you have that relationship already. ask for other responsibilities. see if you can cross train into another position. maybe they have tuition reimbursement or scholarship awards to help you back to school towards a career.