I have a Dexcom CGM and I cannot imagine life without it! The numbers are rarely more than 10 off than when I fingertest. My mom “follows” my number on her phone and she loves it too. As long as your child has on their Bluetooth and are connected to wifi or cellular data there shouldn’t be an issue. My phone is an IPhone and it works wonderfully, and it also does on my mom’s IPad and her Samsung phone. You can also customize what numbers you get alerts for, such as your child getting an alarm at 70 and you can get one at 60 depending on your comfort. I live a fairly active lifestyle and the only thing that really affects how well it connects to your phone and sticks to your body is swimming. This CGM works roughly 20 feet from you so it is good for following your number during sports. I hope this helps and 10/10 would recommend the Dexcom.