Is age targeting accurate?

When using the Ad Manger, you have the option to target your ad at accounts of different ages, for example, 13+. However, this also lowers the size of the pool of people who may see it.

You’d think it’s obvious to only target people who your game is for, but the thing is many people’s age set on their account isn’t accurate. For example, when I was younger friends would set their account age to 13+ in order to get full access to the platform.

So, if I have a game made for a certain age demographic, is it worth it to set the ad to that age? Or is it better to keep it targeted at everyone?