If you look at the statistics, when I was in college in 2012, NH had the highest median age per capita than any other state- in the mid 30's...

@Lisa RispoliI know this was ages ago, but I am curious - how did everything worked out for you?

I actually bought a 4 unit a mile away for $45,000 last year but that needed about 30K worth of work so I feel this is about right as this one is turn key with no repairs needed.The seller financing deal - Sales price $63,500Cash at close from me $50004 year note @ 4% for remainder ($58,500), monthly payment of $1000 with balloon at the end, no prepayment penalties.Monthly projectionsIncome =     $2200Expense=    $220 management                     $220 CAPEX = No problems yet but "Unknown age" on the roof and owner has had property for 20 years                     $480 Insurance/taxes = Total taxes for 2017 were $4982 on assessed value of $78000 plus $600 a year for insurance

As @Nolan Martineau stated, each property will have different Capex due to age of furnace, water heater, roof, AC, cabinets, etc. etc, etc. 

I’ve got the age old question of whether we should sell our townhome or keep it and make it our first rental.This is my first post on BiggerPockets so please let me know if I have left out any information that may be helpful in the analysis.Single Family TownhomeBuilt: 2001Purchase Date: 2008Purchase Price: $270,000Property Tax: $5700/yearHOA: $125/monthWater/Sewer: $1320/year (Must be paid to county by home owner)Insurance: $800/yearMaintenance Costs: $400/year Other planned future costs: Roof (in about 5 years, ~$5000), water heater (in 7 years, ~$1300 including labor), water softener (in 5 years, $500)Current Mortgage (Refinanced in 2012)Term: 15Rate: 3.375%Principal: $140,000Market Value: $230,000 (Upstate NY market with minimal appreciation expected)Rental: $2000/month ($2200 possible but I want to be conservative)I was also considering refinancing to a 30 year mortgage to help with cash flow but I’m not sure if it is worth the $4000-5000 in closing costs to refinance.Normally I would not consider this a good rental property because of the low/negative cash flow.

He achieved financial independence around the age of 30 through real estate investing. 

I am new to rental property investing and I do see the age of properties ranging 7- 20. if the condition of the property good, would I be able to process to pursue 20 years old one as well?

Especially being at the age of 23.

I know because of my age people might not take me as serious, so I want to get as much knowledge under my belt as I can.Do you guys have any advice on what I should be studying now?

The only thing that can't be forced is time -- the age of the oldest CC is always part of that formula, so it probably does make sense for your son to get a (small) CC that he uses only for small purchase and always, always, always pays on time..