Earlier today it was you who told me to do some research. Now it turns out that it is you who doesn’t even know the very basics about hydrogen peroxide, like that it decomposes into water and oxygen, and that it creates free radicals while doing so.
Anyway, it’s a positive attitude that you now care to ask about the things you don’t yet know. Keep up that good spirit!
So, the decay time of hydrogen peroxide. There is no fixed decay time. It strongly depends on the temperature, and on the acidity of the solution. It also depends on the stuff with which the hydrogen peroxide comes into contact.
If you want to read more details about hydrogen peroxide, then rather than writing down a long story here, I’d rather point you to the excellent Wikipedia page about this stuff. I hope you don’t mind, but that page really tells it better than I could ever hope for.
About you not having died – well, smoking is more dangerous than drinking diluted hydrogen peroxide. There are many smokers who reached the age of 60 without serious health issues. But that certainly doesn’t mean that smoking is harmless.
The same applies to an irritating and carcinogenic stuff like hydrogen peroxide. It’s bad for your health, but it doesn’t kill you instantly.
I hope this answers your questions. If not, just let us know.