Dual enrollment (attending community college while still in high school) has become a very popular trend among many homeschool students. After all, the chance to reduce college costs is pretty attractive! There are some great benefits to this choice, but I've found that many parents are unaware of the potential pitfalls when their 16 or 17 year-old student participates in classes designed for older adults.
Our sons attended community college when they were 16 and 17, and one of the most surprising things we experienced was the abundance of pornography. There was pornographic material for sale in the student bookstore right next to the engineering books (because presumably engineers are males). One parent told me that her daughter signed up for an English class, and one of the pieces required for reading was pornographic in nature.
During one of our son's foreign language classes, they showed movies of unclothed people, in order to "experience the French culture". In their speech class, the class and the teacher were great, but another student in class gave a speech that was pornographic in nature. My children were trying hard to act cool, but as a parent, I was pretty mortified that I put them into that situation.
At a college fair I went to, a representative from one community college took me aside and told me to give a message to homeschoolers, that their children are sitting next to adjudicated adults - people who have just been released from prison and registered sex offenders. Community college is an adult environment. There is no way that adjudicated adults can be refused admission.
We were also astounded by the vulgar language. One of the calculus teachers would drop the F-bomb when he spoke all the time. I think he was trying to be cool and trying to fit in with the group. It's important to note that not all teachers do all of these things; we just found these to be true.
Community college is similar to a public high school atmosphere without the moderation that comes from being with other children. At community college you will see people smoking without being concerned that they're smoking, people swearing, etc. They bring this content into the classroom because they're all primarily grown adults; it's not a children's environment.
Students who are perfectionists tend to have more difficulty in community college. This is not an academic problem, because they can get an A with little effort. The problem comes when students transition from community college to a university. When they go on to university, all of the sudden much more effort is required to earn an A. When they realize they didn't get A's because they were a genius, depression can be the result.
Carefully weigh the pros and cons before you enroll your student in this environment; the costs just may not be worth it.