On the other hand, since you’re a Junior in HS and depending on the language, you still have some time to gain fluency. I say depending on the language, because if it’s a European language it will take less time to fluency, but if it’s Turkish or Arabic it will normally take a few years longer. I would do my Senior year abroad in my country of choice, but since you’ve already done study abroad for your Junior year. Maybe a gap year at an immersion school would be more ideal and then apply. However, you must take into account that some European universities have requirements for entering college freshmen that may exceed your US (I’m assuming) HS education level as many students have already begun studying their major while they were in HS. Also, since you studied abroad in their system there might be a loophole for you.

You would really have to look at that school and call. That’s the big difference. Don’t just think you’re under qualified and don’t just take the advice given here. Call and be proactive. It’s always good to do some groundwork in country and talk to the people who make the decisions. You might find that you are perfectly qualified to apply already. As in most cases, you never know until you ask 

Re: #4 – There are some websites that offer housing listings as a good alternative to Craigslist. In Ireland, most people use daft.ie.

Re: #5 – Be sure to check with your university’s international office/finance office that you have filled out all the student loan forms correctly. I apparently had not and was lucky to have an international office worker that helped to expedite my applications after I’d arrived!