You're a first year, so relax! If you were a junior w/ a 3.3 GPA, it'd be different but you have plenty of time to bring that up. Just make sure you get a strong upward trend going and you'll be good. You want to finish w/ a 3.6+ to be competitive so start working toward that. If you can't do that as an engineering major, it may be worth a switch; otherwise, engineering is great.
As far as the ECs go...just get started on clinical, volunteer, and research experience asap and you'll be good to go. Look around this board for more ideas. Use the search function.