@UltraBiel: third mutation? that sounds cheesy. I think the best way to do it would involve time travel in the next movie days of future past.
You think a Third mutation is cheesy? I don't even remember the number of the mutation Beast is in now! And don't forgest it is a movie solution so they can't spend much time explaining what happened to her unless she is the main bad/hero of the movie.
oorrrr say her diamond form slows the ageing process like they have said for mystique and wolverine, problem solved. If wolverine can get with Jean and any other woman then why cant the other characters