You need to figure out your community, if there are a lot of growing families, 2 and 3 bed units will be more attractive.

Age of home, exit price point range, block or stick construction, etc., etc.. 

Best way to raise capital is private money but you need to develop a relationship first and show them deals that you partnered with your parents with.I wish I had started at your age.

My immediate goal is to start out with a house hack and grow from there.

The more you can learn and grow with others who are already in that type of investing, the better.  

Has anyone designated a group of properties as a 'retirement' community with some sort of age qualifier or is there such a thing? 

I first learned about real estate at the age of 9 years old from a childhood friend on mine father.

Parts of Will and Kendall counties seem to be growing as well. 

The one I ill advisedly bought when I got married for the first time at the tender age of 20, which was remortgaged once and has not increased in value at all since (and the taxes have gone up).

How much you reserve depends on age, condition, and a few other factors like 'Do I want to save the reserves because ill need them to replace items' or 'i save the reserves to make sure I'm profitable in the long run'.