Congratulations on booking your venue!! Another thing off the to-do list! My fiance and I booked our venue after having been engaged for three months (though our venue had been holding our date for us since we'd been engaged for one month). We had originally booked our venue for July 2020, so we officially booked it around 9 months in advance. We've since postponed, but keeping the same venue.
Congratulations on the engagement! And you are wise to have booked right away- 2022 dates are going quickly! We booked our venue about 3 months after we got engaged. Once you have your venue set, all the other planning seems to fall into place.
Within a month. We had an eleven month engagement and I knew a lot of venues book at least a year in advance. Our venue only had two Saturdays left out of the two months we were considering getting married.