If it was me I'd take a wait and see approach. For many people the period before and during your hair falling out can bring a great deal of scalp tenderness and discomfort. The last thing you want to be worrying about on the day is being uncomfortable, be it shoes, spanx or scalp! So I'd be prepared for any outcome. Have a gorgeous scarf on standby, a lovely hat, and a wig. There are wig hire places so you don't have to buy, simply rent for the occasion.
The way I look at it is that in years to come you don't want to look at the photos and be reminded of a problem, but rather see the joy of the day. Do what feels good for you. Congratulations and mazel tov! Let us know what you decide. K xox