Building Multifamily Home in San Diego county

So, I'm still trying to get my first property and this time around I'm contemplating this triplex in El Cajon which sits on a large lot. Although, the possible development is not my primary reason to consider it, it is there for the take. So I wanted to get an estimate of building 5 other units on the lot and also learn about any potential pitfall. The zoning is RM2200 meaning with the given lot space, there is a possibility to add 5 more units in the near future. Do you guys think that it'll be a tremendous risk given the fact that I'm just getting started and should focus on getting something "safer"? I personally tend to strive the bigger challenge.