Is it average that 10 YOA pitchers throw at 45 with better than average control, or is this DD special? If specail I would be very careful which PC you choose and how much she practices to avoid "overuse". I find it amazing though that someone that just turned 10 and has been pitching for 6 months is throwing 45 mph. To put into perspective, the girls in the Big East Conference final were throwing low (very low) 60's. In my opinion, you may have someone special there. Do you have any video?
Girls mature at different ages and rates and some girls throw harder than others more quickly. 45 at 10 is pretty good but IMHO still too early to think about D1. In our area the better 10u club teams have pitchers who throw at that speed or higher regularly. We faced more than few pitchers at 10U in the upper 40s. They were all softball age 9. The really good 10u eligible pitchers who are 11 usually move up to 12u.