I recently had to do similar math to see where I would be after 1 and 5 years, was very surprising how different the scenarios turned out. Very clear cut what the best financial decision was.

You need to calculate where you will be in 5 years for a few different paths, and include rent, PMI payment, equity, mortgage payments and do this for a few different interest rates. It will take a good evening to run all the numbers but the answer will probably be clear.

I would run these cases for 5 years out

1) buy now: 4.5% w/ PMI, but you get equity for 5 years, zero rent and deduct interest payments.

2) buy in 2 years: 4.5% w/o PMI, include 2 years rent, 3 years equity growth, and deduct interest payments.

3) buy in 2 years: 6.5% w/o PMI, include 2 years rent, 3 years equity growth, and deduct interest payments.

I would guess case #1 will come out the best but you need to plug in your own numbers.