I had a 2011 13" MBA and switched to the 11" model in 2013. Still love it, I'm 67 and wear glasses, but have absolutely no problems with the screen. I don't see where retina would make any difference. The dot pitch is already very fine on the 11" MBA, I can't see individual pixels at a normal reading distance.
I did adjust font sizes in some individual programs when I switched from the 13" to the 11" MBA. Apple Mail was the biggest problem for me, but there are menu settings for the default fonts in the Apple Mail prefs.
But if you really "can't see the font" regardless of what software you're running, then perhaps the 11" MBA just isn't for you. I suspect this says more about your vision than the quality of the Mac screen. You could visit a store that sells the retina MacBook and see if you find that screen any more readable.
I had the 13 before, I bought this one as I have to carry it around.
I have all the fonts large enough now, (except) for the icons and print on the finder