UCSD Undeclared Major or other UC's

I applied to UCSD for Mechanical Engineering but was given undeclared major. Should I go to UCSD and see if I get into engineering? I was accepted into my major at UCR and UC Irvine. Should I consider those instead?

Yes, you should consider the other schools. Getting into an engineering major as a student is very difficult. I don’t know specifically about ME though. Hopefully someone can address that.