The answer would be an Oxymoron.
Kennings-a compound expression in Old English and Old Norse poetry with metaphorical meaning, e.g., oar-steed = ship.
I don't know if this is what you ment. xD
Answer:
Math
Explanation: I’ve always had a problem with math. But I know that if I keep practicing then I’ll get good enough to be good at it in collage
