I just got my first ukulele and as I was tuning the strings I noticed it didn't sound right. On my tuner it says e when I play the c string and c when I play the e string. Someone please tell me how to fix this.
Well, you have to tune them!
Rotating a tuning peg one way tightens the string, raising the pitch. If your E string is playing a C, rotate that tuning peg until your tuner shows E.
If your C string is playing an E, you want to rotate the tuning peg the other way; this loosens the string and lowers the pitch.
Actually, I hate to say this, but are you holding it correctly?
If you are a right-handed ukulele player, the C string is going to be the 3rd closest to the ground string (headstock is pointing to left). It's possible that you are holding a right-handed ukulele in a left-handed manner, or vice versa. If so, the G string and A string would also be switched in a similar fashion, and tuning them opposite might not be easy to differentiate.
The standard way for right-handed ukuleles to be played is for the headstock and neck to point to your left, and for left-handed ukuleles, to point to the right. This said, you don't necessarily need to switch if you've reversed the two; the string tensions are very similar, and tuning a C string to an E isn't going to rip apart the instrument or anything. In fact, some left-handed players use right-handed instruments turned upside-down.
If you are holding it correctly (or in whatever way that you desire), then I'll defer to Richard's answer.