I want to replace an old 60"X80" sliding glass door with a newer BIGGER sliding glass door (approx 6" wider, 66"X80"). I'd like to think I can cut out space for the bigger door. Is that a feasible plan or ill advised?

Hi folks, Our living room has a sit in window with three glass windows. One of our kids bumped the large middle pane (say 5'x4') in the spring, causing a crack on the internal pane (external pane is fine). [ATTACH]35096[/ATTACH] These windows are on our "to replace" list, but we'd rather hold off for another year. Getting our roof done was this years scheduled reno project - being hit by another few thousand dollars to replace all three panes (and redo the sit-in area) would be a real...pain. Reviewing other postings on the forum, I see that there are no quick, easy fixes (didn't expect any). My question is - what Bad Things could happen if I delayed replacement until next summer? My thoughts: 1) Condensation (seen from other DIY posts). Not a big deal. Won't look as pretty and may cause minor mold inside, but I'm planning to replace them soon enough anyways. 2) Window fall apart?? Is this possible? I wouldn't expect any more major cracking now that its gone all the way across the window, but temp variants may do something wacky. Any suggestions/concerns? Thanks, - C