Should i get an expensive first rental property?

[Mark Johnson]

So, i am a recent college grad and just moved to Chicago. My girlfriend and I are going to be getting a condo hopefully by next year. I was lucky enough to find a good job after college and can possible afford a 100k downpayment by next year. 

I would like to start investing, however my girlfriend wants to buy a nicer condo instead. We compromised and agreed upon getting a 4-plex, living in one and renting out the other three. Chicago's market is very expensive (for me at least) and my girlfriend has very expensive taste as well so the cheapest place i have found was 800k for a 4-plex. 

Would i be able to continue to invest in cheaper apartments if i still have over 600k left to pay off on my 4-plex? I obviously plan on having the other 3 units rented out. Im just not sure how it would work out if i had a high debt to income ratio even if i had all three units rented out. 

Thank  a lot for your insight guys!