Originally Posted by Hawkingbird
My thoughts exactly. I don't see how an event that appeared to happen after their births would change the day of their births.
Yeah, events altered after 1973 cannot change anything prior to that date.
Back to The Future 2 (the chalk board scene) explains it best.
When all is said and done the events of the original trilogy will only exist in an alternate reality allowing for vast creative freedom with the current franchise. I mean, in a follow up to Days of Future Past, Wolverine can join the X-Men now.