My friend, dont be discouraged. If your have prayed about it and you are convinced it is what you want to do, please go for it.However, you must brace yourself for the challenges which some of the respondents have already mentioned.I am actually thinking about the same biz amongs others I am considering as alternative source of generating funds.

Like a few mentioned, you will need to address issues like power (phcn), I am thinking of investing on solar to combat that.
Security is quiet important, you may need CCTV, good security outfit etc. Security should be both internal and external. You may consider time of biz (closing time etc). I know a supermarket where I live (De Prince in Gbagada), that came up with an entry gate like what you have in the banks,that allows one person at a time and checks at the gate of your receipt.It may not be perfect but at lest something.Where to source your goods and price is also very important.

Location is important,but you dont have to go to Ikeja,Ikoyi,Lekki to start (you may when you grow bigger),there are parts of the country that is developing and population is increasing, if you get it right in terms of strategy and pricing etc, you can make it, in terms of numbers. You can come to Gbagada and find out how DePrince went about making it. I intend to do that when I am fully ready and yes I am thinking of starting in one of the new areas outside Lagos. So Ikorodu will not be a bad place to start. Do not despise days of little beginning, just be focused,hardworking,strategic (plan properly,do your market survey etc very well) and pray well (No matter how hard you plan, you will face unforeseen challenges). Hope to see you at the top. All the best.