Would it be okay for me to donate blood in September if my surgery is in December? (1st time donating) What about allergy shots?

I am scheduled to give blood mid Sept for the first time, and I wanted to make sure that was okay if my surgery is in Dec. I am having an extended tummy tuck and breast lift with breast augmentation after massive weight loss. I am 18 years old and weight approx. 155 lbs. I also get allergy shots every other week, should I postpone them for a while around the date of my surgery? Thanks!