15 dB of gain is a reasonable amount when dealing with typical cable and splitter losses in a home. But a deep fringe amplifier is easy to overload which is why I ask for the following information; Your FM Fool signal report, so it's possible to tell how strong your signals are. A TV Fool report would also be helpful, given the antenna and amplifier are going to be passing the OTA TV frequencies as well, regardless of whether you connect a TV. What make and model amplifier are you considering? And finally, will there be any other receivers (FM or TV) connected.? If so, how many?
Generally speaking, an amplifier can be helpful if you have FM signal levels below -60 dBm in the air. Also, the best place for an amplifier is at the antenna, not the receiver. All of the losses between the antenna and amplifier subtract from the signal to noise ratio and can not be recovered because the amplifier will amplify both the signal and noise delivered to the input.