They are only 12months for a short period of time. If you have 2-3 openings in Sept then I would assume you'll end up with more 12month olds. If hold off filling this spot then you will quite possibly end up with a 12month old filling it later and end up with 3-4 young ones at once (which has pros and cons).

Would you be able to 'hire' a young student for the summer months, like a 10-14yr old to help push an extra stroller/pull wagon to the park and help out? Any tweens in the neighborhood? They usually love doing this type of work, can make a few bucks but not cost you too much.

I recently filled my 5 spaces. I had only 2 children come through for interviews that were over the age of 12months (at their start date). One was the sibling of a 12month old (so 2 spots) and the other was 16months old. I have no idea what the rest of the market is like but I found I had only moms on Mat leave coming through. Hence my group of 11-15month olds. We stay on site so it's not as big an issue, and while it definitely is a lot of work I know they will soon be 2, then 3.