why wont it let me enable tracking if im 18

Click on this link to learn what it means if an app asks to track your activity --> If an app asks to track your activity - Apple Support

"In some circumstances, the "Allow Apps to Request to Track" setting can't be turned on, including: 

For users with child accounts or under age 18 by birth year, signed in with their Apple ID*"

Make sure you have the correct birthday set. If you recently turned 18, try logging out of your account and back in again as worked for multiple users in this topic --> App Tracking Age Requirements Issue - Apple Community

Click on the link to read how to 'Update the birth date associated with your Apple ID' - Update the birth date associated with your Apple ID - Apple Support

If you wish to ask Apple about this:

Choose your country or region - Official Apple Support

Do you know for sure it was not a "bug"? I've tried all the different steps posted in this community and nothing worked. I even turned my phone off to have my device have a fresh look at Settings and this didn't work for me. I then noticed there was a software update so I installed it. This is what worked for me and maybe for others.

This may help you. The pic below is self-explanatory

Thank you. I followed the pic and it’s still grayed out. The only way I can turn this on is if I sign out of Apple ID. Any other suggestions?

Sometimes the answer is to check your software to see if there is any bug fixes. This was my case as I'my way over the age limit. I updated to iOS 17.5 and now it's available.

Do you know for sure it was a "bug"? Updating iOS may simply have gotten the device to take a fresh look at Settings as I suggested in my earlier post.

Any other suggestion as it worked because I signed out of my Apple ID? Once I signed back on, the option to turn on the tracker was greyed out again.