How late will I be allowed to stay out? I'm not a party-goer at all, I'm just curious about what time is the best for a young girl to be at home.
This depends from host family to host family and the city you live in. In addition to you being a girl, you are someone else's daughter - so your host family will be extra careful. Curfew rules will depend on whether you go alone or go with friends/family. So while they may not want you to venture out past 8/9pm by yourself, you may often go out with friends/family for dinner/movies etc. a bit later.
Indian days are usually from 6-6.30am to 6.30pm. By 7-7.30pm it is usually dark all year around. Some parts of some cities (like Mumbai/Bangalore) are much safer for women compared to others and your hosts will make the judgement.
How hard will the classes be? I almost always get As, occasionally a B or B+. I'm not lazy and I study. But I'm afraid Indian classes will be much harder/intense than I'm used to.
If you are not lazy and you do study - you will be ok. Indians exams are infamous for requiring you to memorize some things, but you will be able to manage. But you should know that few indian schools allow calculators in class, and most homework is handwritten. So if you math is weak, or if you rely on calculators for basic math, you may want to practice that.
Student to student discussions in class are few (if someone asks a question, you will not be answering it unless the teacher asks you to answer it). You ask Qs to the teacher - and the teacher answers.
What will people think of me when it comes to religious and political views? I'm an atheist and have quite liberal views, and I'm not sure that this is looked at kindly by most in India.
A majority of indians are hindu - and you most probably are christian by birth and atheist by choice. Nobody will mind. They may ask you if you want to visit a church each sunday - and they will comfortable with a no. But you may want to visit the church the first week or two, because, you may bump into other exchange students/visitors etc.
Whether you are an atheist or not is not as important as whether you insult hinduism (or christianity or islam.. etc.). If the host believes in God - as long as you dont call them all stupid for believing in God - you will be ok.
India is simultaneously more religious than the US, but much more tolerant of science (unlike the US). Depending on the day and if there is a festival, you may hear loud blaring music from temples/mosques and churches.
But while everyone may pray to god, you will find few people who don't agree with Evolution ... or that believe abortion is very bad. LGBT rights etc. are issues that are not very commonly discussed - but people generally dont care too much.
But do remember - you are in a different society, it is still a quite free society, but if you start expounding on the equality of men and women and how it should be ok for a girl to wear daisy dukes to school.. (or while going out).. it may not fly.
And last, do you have any tips for me in terms of female safety?
India has fewer rapes etc. than most of the developed world. So even with all the news.. it is not that dangerous.
But groping is quite prevalent in India (primarily in over crowded public transport and sometimes in crowded areas). But you will be protected and your host family will take care of you and you most probably will not see the inside of an overly crowded bus.
I would suggest wearing clothing that the local girls wear.
But, you will draw attention as a american girl. Indians generally expect western girls to be slightly easier than the typical indian girl. So you may have a lot of fans as soon as you join a school - but they will drop off as they realize the reality.