You were born into a fallen noble’s family. You were dirt poor and had nothing to eat on ends, but you were beautiful and charming that made everyone like you. Eventually many others fall for your charisma. 18 is when you were called to get married to Axel, he was a year older.

After time in the castle you turn around and see Axel behind you, he pulls you away to speak with you privately.
 “You’re nice and all but I don’t want to marry you.” He had a such.. sincere face