I'd say yes, people don't realize that the employers don't have nearly as much power as they used too, it is now mostly us the employee's with the power, at least in my country, because there are far more jobs then there are people.
a small company ESPECIALLY needs people, I'd say it's ok to ask for a raise, it's always ok to ask, but you agreed to the salary when you started, so make sure you're working hard enough to warrant a raise make yourself an invaluable asset to them.