One investment property done, what's my next step?

[Tim Wasson]

I bought my first investment property a little more than 2 years ago. It's a mixed use building with 2 commercial spaces on the bottom and 3 small apartments on top. I bought the building in very rough shape and have spent the last couple years spending a lot of time and money renovating (but only income from the building, not my own!). It is now fully leased and grosses $1700/mo. I owe $50K on the building. 

Now that the building is mostly passive income I'm wondering what my next step is. I talked to my mortgage broker and he says I may be able to use the building's equity (he estimated $70K in equity, that the building should be worth $120K based on the monthly gross income). 

I'm half tempted to see if I can use my equity + partial seller financing to purchase a much larger property. In my area there are several 10-20 unit apartments that are $500-600K.

As attractive as this seems to be, I wonder if it's too much, too soon in the world of real estate investing. What does Bigger Pockets say? Should I stick to duplexes or smaller multifamilies for a while or make a big jump now? 

If it matters, I am 39 and not a full-time investor.