You should always trust your instinct when you open your business. If it doeesn`t feel right that is a warning sign for you to pay attention. You could ask your neighbor exactly what he is selling and how would he feel if you sold something similar. Perhaps it could be complimentary.
The others are right also that many neighborhoods have several stores or shops that offer the same service and they all thrive.
If you do decide to open your business. Take every opportunity to collect mailing addresses and e-mails so that you can keep in touch with a unique newsletter or e-zine to your clients and develop relationships. That can make you unique and your clients will remember your personal touch. Kat.