I'm not a native speaker of English, but I lived in this western country for gazillion of years now.(since I was a child) By the way in my country you can return to education for secondary education at anytime with no cost. You can also leave secondary education(drop out) at anytime you choose without being called Hikikomori.
There are also people aged 65+ in school we do not discriminate.
Anyway back to the topic instead of it has been, I highly suggest going with "it's been raining/rainy"