So, I am 20 years old, and I am a college student studying aerospace engineering at Mississippi State University in Starkville, MS.

Usually you have to show W2's from a job for a couple of years, or much shorter if you get out of school and get a job that's directly related to you field of study Also if the 4 plex cash flows better, that might be easier for you to qualify for, because your debt to income level will play into how you qualify... check with a lender. 

Which got me thinking I should do comparison study on cheaper property, with better cashflow.

well, if you're a newbie and aren't sure how to move forward then you need to return to the drawing board. get some more researching and studying in. some opportunities will be a bit much from a newbie perspective. there's plenty of information available here on BP for homework purposes.kudos,Mary  

Hey guys, anyone has an idea what to study for the real estate license exam in California ?  

Study local rentals, where they are priced, what amenities they have, and decide if this house meets the needs of a tenant

Hi Anthony, I'm new to investing but from my knowledge of all the case studies in business school, the market research section could just include overview of your target area (you could even break it down to a specific neighborhood), including the details you listed, and then rental data (i.e. what is the profile of renters in that area, types of homes and rent ranges).

We have about $20,000 saved up and have access to private money.We have been studying the BRRRR method and plan to implement that strategy.

I study and read a lot on the subject and do I really need to brand myself and get an LLC before diving in?

With that said, if you're asking this question, you need to do some serious studying and learning before you proceed in any direction.