I am close to your age and had a total left knee replacement on 1/6/12. My doctor tells me I am 4 weeks ahead of most people in healing. I started back to my job {desk job} full time this week and I am pretty much worn out by the time I get home.
My knee would not give me problems at Disney right now with a
scooter, but I greatly underestimated how tired I get, so I would no way be able to enjoy Disney now. If I go to
Walmart shopping, 20 minutes and I want to leave. I thought I was tough but I do not think I could handle Disney any sooner than 12 weeks post op.
We are going for 2 weeks in May and I have already reserved a scooter. Hopefully I will be able to walk without it more, even though my right knee also needs replaced
Saying all this, everyone heals different and I also have a 16 hour drive to get there. So it may work for you. You will know at 4 weeks post op whether you can make it.
As others said make sure you get that physical therapy and do not make the mistake of missing taking your pain meds. I have several friends and relatives that have had this surgery and they are all glad they did so do not be discouraged, and I wish you the best of luck.