Average Lifespan of a Chihuahua and what is the age of the oldest chihuahua

Just wondering because my chihuahua is 18. And I'm worried :\

Well I had a look on the net and some sites say 10 to 18 years but other also say that it's not unusual for them to live 20 plus years. Just try to enjoy you little dog for as long as you have together, otherwise you may spend years worrying that everyday will be their last.

Our old Rosie got to 13 she died of cancer, we could possibly have kept her going longer but the combination of the cancer and senile dementia made us decide it wasn't fair to her to treat her.

My Chloe lived to be 17 1/2. She was blind in one eye from a bee sting but other than that she remained active and in good health. She just didn't wake up one morning.