Hi there,
18 years, 10 months is when you're finalizing your growth plates. Your growth plates don't fully seal until age 24. The good news, you're at a great height and you're still young - there's potential for another inch or so.
At your age, I was hitting 5'11". I was in your same boat...
Well, I did read about bar hanging, stretching, swimming, running, NUTRIENTS (calcium, vitamin D and sometimes glucosamine), I started to improve posture as well and stand really tall when getting measured. At about 20, after trialling this for 3+ months, I had my father measure me with a standard measuring tape against the wall; I was just over 6 feet tall. Keep in mind, this was at night time....when you are fatigued/dehydrated the most is at night....you may lose a half inch to a full inch (or more with bad posture if you're lacking the necessary nutrients for extended periods of time, or slouching) at that time until you rehydrate your body and wake up in the morning after a full eight hours.
Now, I'm nearing 26; nothing has changed, but posture+nutrients still play a big part. I may have lost a half inch but I'm at 6 feet tall; in the morning, however at night might measure .5 to .75 inch less.
There's definite hope for you. Keep active, consume the necessary nutrients and you'll be fine.