I agree with GRANTS. It shouldn't matter.
If you really want to go to uni then go. It wont do you any harm. Bear in mind though that you'll have two lots of debts to pay off.
But, the longer you're in the airlines the better. Seniority, money and lifestyle all improve with time served.
My suggestion would be, if you really want to fly then do it now.
You can always get pi**ed and puke like a student while you're doing the ground school
CM