Hi Lilian,
Yes, here you are:
Many people did not understand why I did such a stupid thing and therefore they wondered.
If I had taken time to question myself /wondering, why I was going to do it, I probably would not have done it. That I ought to have done, because then I would not have done such a stupid thing.
Please do not bother too much. Just delete the matter if it cannot be sais/understood in English.
"There are many
who wondered
why I did it.
I should have done it too/ I should hav wondered too."
ex: I have bought a car although I cant afford it.
A lot of people ask themselves why I did it.
And t would had been better if I had thought
it over before bying it.
Hope I explained myself well enough.