Girls drive me home from school, why?

Hi
Im not a talkative person in my class (i am with my close close friends) and i dont really talk that much. One day a guy from my class asked if i wanted to go to his car, and he would drive me home. Turned out that it was two boys in the car, but the there was 2 girls, who had the car and drove us home.
Fast forward to today, they asked me again. This time only the 2 girls from before (and their car) they also asked another dude from my class but as u now know - i dont talk with my class that much. They drove him home, and afterwards drove me home. They asked questions and as last time, it was awkward, cuz i dont talk with them. And i also sat in the car a long time cuz the other boy had to be dropped of first, so i sat with them. They just drove me home, as im making this (i came home like 15 mins ago) Why are they doing this? Randomly asking if i want a ride home, i dont talk with them?
I had another question on my profile regarding these same girls, it has been deleted though. (I dont know why) But these same girls laughed at me in a period of time. Whenever we was going from the school to the bus station, to get home, they laughed right when they were riding past me. This happend a lot of times, and in the end i concluded that they were laughing at me, cuz i was observing it everytime, and they stopped talking a bit behind me, and laughed when they rode their bike past me.
I dont know if the last situation has something to do with the one in the start, but i just put it in, so u guys get a better perspective.