Congratulations on your admission to Ivey! It is a really great program. If you believe the school satisfies your criteria for what you expect from your MBA program, then I think it is definitely worth strong consideration. If you pass on it now, you cannot expect it to be there for you in the future, and there is no guarantee you will get into schools you apply to in the future. Likewise, you should consider if the schools you would apply to are worth that risk--if they are on par with Ivey, then why would you wait a year? Why not just go to Ivey? It seems like you are concerned that Ivey is not the right fit if you are continuing to "shop" for an MBA program. Perhaps you should make a list of questions and/or concerns and contact the school? It seems like if you are truly ready now and do not want to wait, then Ivey is a great option for you to start this fall.
In the event you do pass on Ivey, your age is not going to be a negative in the admissions process. However, you should understand that Ivey will probably not grant you a deferral nor re-admit you next year if you turn the school down this year.
Good luck,
Lisa