I moved here at age 22 also not knowing anyone in the city. I just moved to try something new and have some adventure. I'm now trying to move OUT of the city.
Seattle IS expensive to me. I'm from the Chicago area so I'm used to really good $1 drink specials when I go out to bars. They don't really have that here. You won't be able to afford a car if you live in the city, but the public transportation system is below average. Then again the only other city I've spent significant time in (Chicago) has great public transit, so I might just be spoiled.
Jobs...eh. It's like this. The economy is actually good here, unlike the rest of the US. We have Starbucks, Amazon, Nordstrom, Microsoft, Nintendo, just to name a few. But we also have one of the most educated populations in the country. I know people with Masters degrees who are baristas or work retail for minimum wage. Minimum wage is $9.04ish though which is better than most of the country.
Overall, I think Seattle is a GREAT place to visit especially in the summer when the weather is beautiful. Had I known what it would be like before moving here though, I honestly wouldn't have moved here. It got old after the first month of living here to be honest.
Making friends shouldn't be hard as long as you stay involved, get a job, go to school, join a group, etc. People here are stereotyped as being introverted and stand-offish, which is kind of true but you get used to it...sort of :/
Also, UofW is a great school and if you get in you should probably just go...unless a better school somewhere else accepts you. The University District is an awesome neighborhood and is one of the few Seattle neighborhoods that actually has affordable stuff to do.