If you are in a boot and unable to support your weight easily ; I would cancel
I went to Rome a few years back 3 months after breaking my lower leg. By the time of the trip I was healed and walking normally without support but had PT up until the week of the trip.
Still the amount of walking I was not used to and my lower leg, angle and foot swelled so badly starting on the airplane flight and never let up.
Ended up having to buy a pair of sandals in Rome to walk in as I could not tie any of the shoes I brought with me.
I suspect my injury was more serious but was also much further along in the recovery process than it sounds like you are.
I was glad I still went and managed by just walking less than I otherwise would but felt if the trip was a couple of weeks sooner I could not / should not have gone. Also, I was not on any tours or with a group ; afraid if I was I would have held them up or hurt myself keeping up with the pace.