I think this an American product so the half ounce size doesn't give a clue on age as they still sell products in imperial amounts. If there is a web address on the packing its probably less than 15 years old. If there is a bar code on the pack it's less than 30 years old..
Rupert
March 2019
I can answer this question...
how old is an 1/2 oz container of heddy fabric mending adhesive?
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix general clothing.