Mother of IVF twins born in late August. Depending on your age and how confident you are that the transfer will be successful, I would vote for avoiding an August birthday. Sure, plenty of kids with August birthdays do fine, while others get held back. It might work out fine, but if you don't hold back, it can be hard always being the youngest in a grade (especially in schools or areas where redshirting is common).
Whenever someone tells you how great their young for their grade kid is doing, ask how old their kid is. There are decided disadvantages to being the youngest in the grade, some of which aren't apparent until a kid is older. For example, in Maryland, you can't get a driver's license until you are 16 years and 6 months old. That means that if you complete your driving requirements and get your license the first day you are eligible, the earliest you can drive is February of junior year. That gives kids only two summers as drivers before college and means that you will be driving them around for much longer. There are also jobs and education programs that require a minimum age of 16, which again, limits opportunities for summers during high school. If given a choice, I would not opt for an August birthday. My kids turned out fine, but I regret not holding at least one of them back.