Of course. We recommend you to sign up for Medicare three months before reaching age 65, even if you are not ready to start receiving retirement benefits. You can opt out of receiving cash retirement benefits now once you are in the online application, then you can apply online for retirement benefits later.
Are you currently choosing not to enroll in Medicare Part B?
Yes, I  wanted to do so at a later point of time.
In this case your coverage may be delayed and you may have to pay a higher monthly premium for as long as you have Part B. Your monthly premium will go up 10 percent for each 12-month period you were eligible for Part B, but didn't sign up for it, unless you qualify for a "Special Enrollment Period".