For a casual run, you are somewhat under-leveled. Most players will be max rank by the time ELK is fought, or at least very close. If you didn't know, max rank is 27.

How much side-quest stuff did you do? Most medals are acquired through doing quests, or through exploration in general. Your MP is definitely lower than most would do, but you should be able to succeed with enough usage of items and TP.

Also, this isn't exactly the best place to ask for help on a first run of the game. You'd be better off asking about it on the official discord instead.