Dress shopping when you know your body will drastically change?

My ceremony is 11 months out. I’m moving across the country in September, but was told I may have a pituitary or adrenal gland tumor that’s leaking cortisol. Once I move, I need to get set up with a GP to refer me to the research hospital for testing. If they catch this thing, I’ll need brain surgery or chemo, depending on if it’s caused by a tumor or just abnormal cells. Thankfully, it’s not cancerous. But the result of treatment would not only be a drastic weight loss, but a drastic change in weight distribution. I have no clue which dress shapes will look good on me because I don’t know what my proportions will be for another 5 months at least.

i keep seeing to dress shop a year in advance. Our engagement will only be a year total. How screwed am I if I wait til after I recover from surgery to shop?