To avoid PMI insurance there is a couple of things that the mortgage broker can review with you. My broker was awesome and worked the numbers a couple of ways and we did what worked best for us. We did have 20% to put down on the new house so there was no PMI insurance for us. The other thing you need to figure into your figures is closing costs.
1800 a month mortgage at 22-23 is a lot of money, and I couldn't count on getting a raise. What a company says they are going to do, and what they actually do are normally two different things. Unless you have it in writing from the company I wouldn't count on that raise.
Not trying to be mean, just giving come constructive advice.