Career Choice (Property Management Vs. Sales)

A few weeks ago I started a job as a sales rep for a small medical supply company, and I'm not crazy about it. Before I started this job I interviewed for an assistant property manager position, and they just offered me the job today.

My real estate goals are to be a buy and hold investor of small multi-family properties (30 units by the time I turn 30 years old), and the owner of the property management company has over 100 units and the management portfolio is over 400 units. 

I'm having a hard time quitting a job for a small company where I know and like the owner, to start as an assistant property manager even though I think that it could be a good career choice to help with investing/managing my own properties in the future.

I guess my question is... How beneficial could a job as an assistant property manager be to my investing future?