I've been getting a card or two a year to increase my limit (indirectly lowers utilization as well if you don't charge it up) - it does hurt the overall credit age though 

And in certain markets like SF bay area if the sewer line is of a certain age its mandatory to replace it before close of escrow its a law.

How were you able to invest in real estate at the age of 16?

Without knowing your age, I like the idea of pushing additional savings into good, no load index funds (I like Vanguard's S&P index but there are plenty of others) through a Roth if you're young enough, leave the rental portfolio as is and pay the debt down to nothing, since you're not inclined to really work at growing that end of it. 

It’s awesome to see someone starting their real estate journey at such a young age with a clear vision and determination.

My daughter will be school age a year or so after we move in.

However, I know that I do not want all my income to be reliant on my day job and live to watch my retirement account grow.I am probably doing better than a lot of people my age but am eager to take the correct steps to build a real estate portfolio.

Yep, I already knew that I won’t retire by my job ages before I started working, this job is just the pathway for me to open my own business.

That is why we are giving funds at age 30 and 40.  

I am 49, (not far from your age) my business partner is the same age as me.