No worries, the community here is fairly friendly and supportive.
There are different string types from Aquila. Most common are the Super Nylguts, New Nylguts, and the Red Series. I love the latter, but would probably get the Super Nylguts or New Nylguts for your instrument. They are very robust and you can find them in nearly every music-related store. Aquila strings are also fairly inexpensive. They take a bit to stretch and hold their tune, so the first few days you'll have to re-tune a lot. That's normal, really.
Speaking of which: Did you get an electronic clip-on tuner? Initially, and also with new strings, new ukuleles always go out of tune, which makes them sound pretty awful. That happens with expensive ukes, too. Those tuners cost a few dollars only (out of curiosity I bought a $50 one and it wasn't better than the $5 tuner I had). A tuner on your phone will do in a pinch, but a clip-on tuner is easier to use, more accurate (no environmental noise), and generally good to have.
Like WCB said, inexpensive and mud-range ukes often benefit from fine-tuning, called a setup. Those are more or less small adjustments to ensure best playability. But I think you will find your instrument will sound better with new strings already, and proper and frequent retuning to make sure it's in tune. Technique matters also.
Sounding terrible is also normal when starting out. I know people always say the ukulele is an easy instrument to pick up and learn, but honestly, it wasn't and isn't that way for me. Even strumming (and holding the darn thing!) were pretty big obstacles. I still work on my awful rhythm and timing, and my strumming isn't anywhere near where I'd like it to be. Fingerpicking, after I spent time training my ring finger, comes more naturally to me, at least chord melodies. Other forms of picking (that aren't chord based) are difficult for me because the combination of remembering which string to play, fretting it properly, and doing it fluidly is super hard for me.
So no, for me, the ukulele wasn't easy to learn, and I sounded awful for quite some time. You know, when the elderly neighbor rings and says with an annoyed voice that she is going to take a nap now and to please be a bit more quiet? I'm now at the point where she walks by my open windows and says, "Oh, hello, minstrel!" And comments on how pleasant something sounded (fingerpicking patterns and chord melodies impress people easily, practicing the hard stuff doesn't...).
Anyway, stick with it. Money and better instruments come along eventually, but starting when you're a teenager is an invaluable thing that you can't do later on. You're young only once. Hey, I know, I resented all of these trite lines when I was a teenager, all the blah blah and the patronizing-sounding stuff from people who didn't make productive use of their teenage years either. I had a nice organ and my grandparents never tired of telling me to use my early start, but there were a million other things I found more interesting than practicing ... didn't help that some boy, a relative, came by and played on my organ like a god, and I got the "Wish you could play like that" well-meaning-but-ultimately-idiotic looks and comments. At least you have YouTube, I had a bitchy piano teacher who turned me off of making music for many years.
Anyway, welcome to the forum. Hope you stick around!