If you want to check with that person first, it would be preferred to wait, so that we can match things up correctly and process your enrollments together.

Since most people do not object to receiving upvotes (and there is no obligation on the person that you sponsor to ever do anything), I don't know whether members are checking with the people they sponsor before enrolling or not. I suspect that most do not.

Also, you can enroll with STEEM (we welcome SBD since it's worth a little more right now, but the actual fee is in STEEM - if you send SBD instead the extra will be treated as a donation).