Depends on if you have a nanny lined up or not. Interviewing a nanny can take time and finding someone you like can be challenging. The timing is good, as many families with elementary school kids keep their nanny for the summer before elementary and then those nannies are available (not saying let go every year but the nanny of someone who was the family nanny from birth- 5 kind of a thing). So Aug / Sept is a more naturally time then say Jan. But, you want to be looking and intervening now.
Finding another family can be super simple - place an ad, meet, talk, agree on terms, start. But if you have specific requirements or unconventional schedules or requests, finding someone else can harder.
I don’t see a down side to starting now. Waiting only increased the stress since you have to find people faster. It is not like you are trying to set something up a year in advance. Now seems right.