I don't think she looks 45 years old in this video. All that really matters is how she is in the role which I guess remains to be seen. I think Anita can stand to be slightly older. Rita was 30. Karen Olivo was 33. Also in order for this play to have the gravitas it needs they can't all be 19. A 19 year old musical theatre performer doesn't even begin to have the life experience of these gang members in the 1950s. Arthur Laurents says so in his book, that while they tried to cast the revival age appropriately millennials don't carry this kind of weight with them. They haven't been through a war, they haven't seen anything. A 19 year old in the slums of New York in the 1950s is a far more mature person than a 19 year old musical theatre actor.