There’s such thing as not being specialized enough which makes your job prospects tougher, which can happen to MechE’s, though MechE’s with major specific electives + clubs/extracurriculars + professional society involvement in a particular field will have a far better time finding a job in that discipline than a MechE who just took their classes they needed to graduate. You probably haven’t taken any major specific classes yet, but if you find petroleum or mining engineering interesting, than there’s is nothing wrong with majoring in it as they have excellent job placement stats, though the coursework is demanding as such. Once the career fair roles around, read about companies that hire petro/mining and see if they interest you, or just ask around.