I'm pretty sure that's an exaggeration. Can you count to ten? Do you know what 8 plus 5 is? Do you know what 3 times 5 is?

Seriously, start here:

https://www.khanacademy.org/math

If you get stuck there are on-line resources and people who will help. If you don't make time for it or put in the effort, nothing and no one can help.

Everyone starts from the beginning, some later than others. Take your chance now, it's never to late to start, but starting sooner gives you the best chances.

You did manage to calculate your age though. You either knew your birth date and substracted it from the current date, or you remembered your age and added 1 every time your birthday came up. Either of these methods requires knowing some math.