The problem is that you have learned to read and write English before you learned to speak it.
Consequently you are always translating from your mother tongue (L1)
into English (L2) when you are speaking. This causes the time delay.
Babies and children always learn to
speak first, and to read/write later. That is the natural/normal way that language is learnt.
Age is also a factor. Some studies of the brain indicate that L1 is
stored in the Broca's area of the brain, but that this gets
substantially filled up by the time a person reaches their teenage
years.
So at 40, it is not going to be easy to learn L2. The brain has to force the new
language in somewhere else, and then the brain has to find where it has
put the new information!
However, learning continues through life, but for most people it is harder when we get older.
I suggest you find some English friends, listen to English radio, watch English tv.
Try to associate regularly and often with native English speakers.
(And maybe have some lessons with a qualified speaker.) Don't give up!
It's not easy, but you will be surprised how quickly you will
make progress, and you'll be conversing naturally in English because
you will gradually begin thinking in English, or rather, you won't
actually be
thinking in English because your responses will automatically be in English! It's true!
Best wishes.