Congrats!
Keep this attitude and you’ll go far! Good luck with your next step in life.
How I did it: I started college strong - took my classes very seriously and got my best GPA's the first two years of school. That allowed me the needed cushion as my classes got significantly harder as an upperclassman. I didn't start college with this goal, but once I realized it was actually possible, it was more motivation to do my best.
Lessons & tips: Don't slack off, even if you are undeclared, take your intro classes seriously - you may be surprised how much they can impact your overall GPA in the end!