I can understand why Susan never took sword lessons, well there are probably numerous reasons.
1) No one in Moperville trains in the usage of long swords, at best as some state, only Fencing, which isn't the same. Closest thing might be to join an SCA group but dunno how that would work.
2) Some suggest that she should have no problem getting training because she's rich, but Susan might not want her mom to pay for everything, Susan has a job, I'm certain that Susan bought her car with her own money from her job, so if she wanting to get professionally trained, she'd probably pay for it herself, but she might not have the time to invest between work and school.
3)She probably wanted to forget the whole vampire incident and didn't believe she'd ever have to deal with that sort of thing again, we know she didn't want to look at her spellbook after her awakening, she probably didn't want to use a sword until the goo fight. My guess is she kept swords in her summoning chest more as a deterrent if someone tried to mess with her.
4)She might not have wanted her mom to suspect anything happened to her in France, it'd probably be concerning if your daughter came back from a school trip requesting to take swordfighting classes, even if the excuse is that they were told about Joan of Arc.
I never said he had a chance of succeeding.