The biggest mistaker I mad when I started buying deals, we were self managing.

If you supply the materials , and you order the wrong stuff , or dont order enough , and the contractor is there with 5 guys and cant work due to your mistake .

Every GP, real estate investor, makes mistakes, doesn't time the market perfectly etc, looking for the perfect is the enemy of the good. good REITs right now, take a look at ADC - agree realty, does multi-tenant triple net large shopping centers and has better growth outlook than Realty income-O-, 6% vrs 4%, which is also great company, both stand to benefit from low supply of retail space, last 5-10 yrs construction-wise, and thus better rents going forward, and interest rates should fall near term, lowering Cap rates and increasing underlying asset values and sales proceeds (only hold REITS in a tax-sheltered account, 401k or IRA, due to high taxation of the dividends-ordinary income) Good Luck

Seems weird it would make such a basic math mistake. 

They deal with 100’s and the IRS deal with hundreds of thousands, they’ll spot a mistake at first glance.

Basically own your mistakes or short comings.I have only ever given 1 full refund and it was really just to get scumbags out of my property early.

You'll need to make decisions, and do a lot of research to minimize mistakes for out of state investing.

A mistake early in the process will manifest itself later.  

If I calculate the management fee at 0%, my CoC would be 13%.I'm not thinking this is a good deal anymore but I really need some guidance as this is my first investment property and I don't want to make a costly mistake. 

Throughout my years, I’ve learned plenty from mistakes, like underestimating the importance of solid agreements with buyers.