Does having a high school diploma only makes you uneducated?

No... 12 years of school with a diploma does count as educated

It depends what environment you're in. In some places it's pretty impressive to have a high school degree, while in others most people would go to university. It depends where you live and what career you're in.

No. In my town people who never went to college are making more money than people who went. The ones that went are all in debt, can't find a job despite trying hard, and aren't making money to feed their kids. They feel betrayed and bitter. I'd like to try taking some classes, but seeing most people's end result is pushing me away.

It can mean nothing or a lot, it just depends on what you're going for college and career-wise.

No, the opposite is true.