As others said already, you must listen to your body ... and be honest with what you hear!
The second point is do not break your surgeon's rules or guidelines. Their recommendations could vary significantly, but no one encourages you to push early on.
Walking wise, I was doing more at that stage, but most people would be doing similar to you or less. There is no magic number.
Quite a few of us started on the static bike around 1 month after surgery, but just a few minutes to gain mobility and some strength, very gently: low resistance and seat high.
However, I only started swimming after 3 months (my choice), even now only swim twice a week.
And didn't do any stretching until after 6 months (still now I'm not fond of it).
There are many factors why we recover differently: surgical approach, overall health, age, gender, weight, sporting history, activity levels prior to surgery (and how bad was the arthritis)...