I’ve seen students doing CS related internships during the summer after freshman year. I don’t know if that’s considered normal or is it because they have been coding since they were little.
What level of CS do you need to have in order to do internships that are related to CS?
I’d say the students who get them after freshman year definitely had significant prior experience, or knew someone. 
Most internships want you to have taken data structures at a bare minimum to even look at your application. Some also want algorithms and some have a specific level of math you must have taken too.
If you didn’t have any experience, then sophomore year of college is around the time you would be ready. If you had experience, freshman year of college or high school can even be the right time.
I almost didn’t land an internship because I hadn’t taken a data structures class. However, because I had taken well above the required math classes they did changed their minds. It also helped that I had a lot of outside the classroom learning in computer science.
Really it’s all about what you know how to do and not where you learned it. If you haven’t learned CS in a classroom then you will definitely need a portfolio that showcases your skills.
I am a current 3rd year at UCLA and I got mine this past summer, so summer after sophomore year. It was at a startup based in Pasadena, and it was an amazing experience!
Depends on your experience. I have a friend who will be interning at Google this summer (and he’s a senior graduating from HS this year). I think that once you take a basic algorithms and data structure class, you should be ready to interview at most of the places. A few people get internships after their freshman year, but most of them get one after their sophomore year