I cannot lie for which I end up giving too much personal information. What can I do to increase my situational knowledge?

To increase your knowledge of how to act in situations, observe others and take mental notes. Some people are very socially adept and always seem to say the right thing. You won’t be able to BE like them, but you can copy some things about them, maybe some phrases or gestures or body language that seems to come naturally to them.

Since you are already aware that you’re giving too much personal information, you are ready to stop doing that. Even if you can’t lie, it does not mean you need to tell “everything” because, chances are, that will be boring for your listeners, and may even make them uncomfortable. So, when someone asks you a question, you need not lie, but you should stop after a few sentences and see what kind of reaction you’re getting. If the person seems really interested, you can continue. But chances are that, after you’ve said a few sentences, they are going to want to chime in with something about themselves. Let them do that. Then, when they’ve said their piece, you can comment on what they said. Not a lie at all. It’s just “a conversation.” Back and forth — like tennis.