I decided to side with the NCR after being a diehard Mr.House and Legion really devoted fan.
I completed the game many times and sided with the NCR before.
This time I have already done most of the quests for the NCR that can be done (except the End game quests where you have to go to the different tribes) but now I just want to side with the Legion.
Most of the pro NCR quests that have a negative outcome on the Legion (Camp McCarren train, Nelson, the bay that you can pollute with radiation) have been completed but I managed to get some Legion fame and be accepted again by abusing gameplay mechanics.
My question is, is it too late to join the Legion?

Have you completed or failed "Beware the wrath of Caesar"?

I have not, sorry, forgot to add that.
Caesar gave me the quest to kill Mr.House quite a while back.
Oh, and I have the Securitrons upgraded.
I'm accepted and everything.
By my question I wanted to ask if I screwed up endgame (the slideshow) wise or not.