So I scheduled my top surgery yesterday.  (for December)

I have had my heart set on December since the beginning because it is the best time for me, and really.. the only time.  When I had a phone consult with the surgeon he said that December fills up fast.  I couldn't wait..

Problem is.. I want to tell my family.  They know I am transitioning, and they know my name is changing legally this summer.  They are having a "hard time" but I can't really wait on them to be OK with it.  So how/ in what way is the best way to say hey.. I am having surgery at this time?  I feel like that is going to be the hardest for them to hear.

They are doing what they can to understand, and because of this, I really want to do what I can to be upfront with them so our relationship is hurt in an unnecessary way by my transition.

I'm not sure if this will be helpful or not...
I just scheduled my top surgery as well for a couple months from now and I am so ridiculously excited, but afraid to be so happy about it around my family.  I guess over the past couple of years I've realized that some people come to accept our transition with time and others just never will.  I''m learning to stop worrying about whether or not people are ok with it.  When it came to my family, I sat my mom down and told her that I had found a surgeon to do my surgery and that it was very important to me and that I could understand if that was hard for her to hear but I love her and respect her deeply and want her to be a part of what's going on in my life.  Even after our conversation, I know there's a part of her that is struggling with this, but I also know that she loves me and wants me to be happy, and for that reason she is trying really hard. 
Also, please don't feel that you are in some way hurting them by transitioning.  I'm not saying that some of your family won't be hurt, but to take on that responsibility is not really fair to you.  You are doing what you need to do in order to feel happy and whole.  I'm sorry if I rambled.  But seriously, congratulations on scheduling your top surgery, that's really awesome and don't worry, everything will work out, when it comes to transition, a lot of things just take time, but they do get better