We got our daughter a cell phone in 4th grade. She is 16 now, driving and of course will have a good phone. She has always been responsible so we don't have the same hard strict rules as some parents do, however, if she is not responsible with it, we will begin stricter practices.
Check with the school. I sub teach in elementary and a lot of kids have cell phones. I usually see them at the end of the day when the children are getting ready to leave school, especially the walkers and bike riders.
At high school, they are allowed at all times except being used in the classroom. The only time phones are taken up at high school is if they are using them in class. It is free for all in hallways and lunchtime.
We've always had text and that has been very handy for us. My daughter texted me in middle school twice about a lockdown in process.
We all 3 carry IPhones so we have the same chargers, data plans, unlimited texting, etc. I understand that a 10 yr old does not "need" all the bells and whistles that a 16 yr old does.
Just set your rules and don't let anyone make you feel guilty or wrong. You have to do what is right for your family and no worry about everyone else.
Good luck