Is cost a concern at either school?
But if you really want to study engineering, Clemson appears to be the obvious choice. However, verify with the department to make sure that there are not extremely high GPA requirements to change from frosh general engineering to mechanical engineering after completing the prerequisites.
At VT, changing from non-engineering requires a minimum overall and technical GPA of 3.2 to apply, but admission is on a space-available basis (i.e. no guarantee of admission). See http://www.enge.vt.edu/_files/undergraduate/com_requirements/COM_NonGE_Admitted_2016_After.pdf .