Myths first: probably not a red head; not a prostitute; almost certainly not married to Christ, or a mother of 'the blood line of the Holy Grail' (oh please...)
So, facts: she accompanied Jesus on his travels and provided for him out of her own means; Jesus cast seven demons out of her; she stayed at the foot of the cross while the men fled, and was the first witness to the resurrection.
This latter was a big hint that now, in the new age soon to be inaugurated by the gift of the Holy Spirit, women and men would be equal partners in spreading the Good News. To Mary Magdalene even belongs the epithet 'apostle the the apostles' as Jesus gets straight on with urging her to witness to the new resurrection life: 'Do not hold onto me (...) but go instead to my brothers and tell them 'I am returning to my Father and your Father, to my God and your God' (John 20: 17).
(NB. and he didn't add 'But make sure you don't give systematic bible teaching to gatherings of men or at any point in history preside at the altar, as you are only a woman after all and I am a complementarian not an egalitarian...')
Being delivered of evil spirits, spending your own money on someone who was violently killed; seeing them alive again as they send you out out personally with a special mission - all these add up to a paradigm of discipleship which is about transformative and passionate involvement with Jesus.
He seems to like it.