My DD was in the same boat. Though at no time did we ever talk about MPH. We've always just worked on mechanics. First year 14U she was throwing 47ish. Going into her second year of 14U she's now throwing 54-55. Speed comes with mechanics. I don't even own a radar because i really don't care about the MPH at the end of the day. I can tell generally how fast she is throwing just from catching. Her PC does clock her 2 or 3 times a year but does not stress speed either.