when the lie becomes a truth

today i was thinking about lies..a lie is something that happens in your life..probably everyday..everytime you are told something, it could be a lie..be it a big one or a small one or like what people call 'white lies', lies are still lies..what you say to other people or yourself could be a lie..but sometimes when you don't know the answer, and you give a guess, would it be considered a lie?
for example, you were asked 'hows your grandma?' you haven't seen her for the past 5 years, due to certain circumstances, and you don't know how she's doing, so you reply 'oh she's fine' but the truth is, she is dead, even though you don't know it..would that be considered a lie?
and what happens, if you say something, that was true but turns out to be a lie instead?
for example you were asked 'hows your grandma?' you haven't seen her for the past 5 years, due to certain circumstances, and you don't know how she's doing, so you reply 'oh the last time i saw her, she was on life support, so now she's probably dead' because the last time you saw her, she was on life support in the hospital..but the truth is that she's alive and well at the moment..would it be a lie?

but what happens when the lie becomes a truth? would it still be considered a lie?
for example your friend asks you 'did you fuck my mum?' and you say 'yes i did, man was she good in bed!' when in fact you didn't, and he asks you 'no seriously' and you say 'yes im serious' and he says 'would you fuck my mum?' and you reply 'never in a million years!'..a few weeks later you're caught fucking your friend's (poor) mum..so were you lying by saying 'never in a million years'? or when you said 'yes i did'..because at that point in time, when you were asked the question, you had decided that you would not want to fuck your friend's mum, even in a million years (so you were telling the truth at that point in time) but then things happened and you did do your friend's mum, so does that make you a liar? when you bedded your friend's mum it would have made your lie (in the past) about doing her ('yes i did') a truth (at the present)..so does that still make you a liar?

note- none of the above things have ever happened to me and were written just as hypothetical examples..i'm serious! hahahaha