"i think i did the right thing helping my friend or did i not? "
It's not the worst lie in the world, but it's not this simple and I think you know that. If it was the right thing, why not tell dad the truth? My guess is you were putting yourself at risk and you didn't want him to know it. It could be the long drive into the city, maybe going through bad neighborhoods. Maybe she lives in a bad area. Maybe the biggest risk of all is the volatile situation in her home.
It's good you feel guilty! That's because this shouldn't have happened. I also don't get why she didn't call her mom or her boyfriend. This matters, because one thing you want to do is tell her you can't do this again. You can help her come up with ideas to change her living situation, etc. It's important you do this, because you're protecting yourself.