Comparison is the thief of joy

Hi! I'm getting close to my 30th birthday and I was sure it wasn't affecting me until it did. I recently started to compare myslef with other people and ideas on how my life is supposed to be like at this age.

I'd love to read a book that could help me out with this feeling and focus more on appreciation and gratitude. Please recommend ❤️

Also open to receive advice or science based explanation on why do people need to compare themselves to others. Why is this a mechanism we come up with in general?