No, this is not restricted for novices and citizens only. We are all under the "3 minutes window" rule, except for the site administration, i.e. scribes, demis, and Jot, of course. I'm a millenium patron myself and I cannot edit my posts for any longer than you can. I know, it's quite the bummer :-( The only exception to that rule: levels 5-6 in a group can edit their posts within that group no matter if they are a novice or a patron. To sum it up, subscribing won't affect your editing time at all. This is actually one of the rare things it doesn't influence around here ;-)

My advice to you would be to test the post outside AW to make sure it works coding-wise, especially if it's long and complicated with tables and all that stuff. If you want to edit it even after the 3 minutes window, you can always ask someone from the admin, scribe or demi, to do it for you. Not an ideal solution, but it can always come in handy if there's one major problem with a post you've made