The info next to the thumbnail of your footage generated in the Project Panel gives you the format and frame rate. Here's some footage from a GoPro:
I'll bet that your footage is being interpreted as 30 fps because that is the default setting in the preferences.
Change the interpretation of your sequence by selecting the sequence in the Project pannel and then selecting File>Interpret Footage>Main.
If you always work at 25 fps change it in the preferences under Import: