Yes, but you wouldn't know it was different, because it would be your new past.
For all we know it's been done and some or all of our pasts have already been altered.
This is going to sound a bit out there, but I have a theory that the "time machine" is built into our minds and not a "machine" at all.
Quantum physics dictates that the past, present and future all are happening simultaneously, and it is already proven that the human mind has measurable physical effects on matter and therefore reality at a sub atomic level.
Hey, it's not any stranger than suggesting we might all be just a simulation running.:D
Anyway:D my past has near zero regrets, and I could happily go back to most any year/s except when I was serving, but even those years were something I wouldn't want to give up.
