Hey, i was just wondering about wheel sizes.
A while ago i got myself a unicycle with an 18 inch wheel. My girlfriend has one with a 20 inch wheel and it seems quite a bit easier to ride. I presume the bigger the wheel is the easier it is to learn on?
Are there benefits of having a slightly smaller wheel? because i am confident with riding (rode a 5km trip about 3 times now) but i have problems idling…Ive been practicing it more and more lately but i just can’t seem to do it >.<
Different people like different sizes to learn on. It is generally accepted that a 20 or 24" unicycle is ideal for most people to learn on.
A larger wheel will smooth out your riding some but may make the wheel harder to control. Larger wheels are also harder to mount and more intimidating to new riders.
Thanks for the information 
So pretty much, The larger wheels are smoother - but harder to maneuver?
yes that’s pretty much it I have a 16" uni its nice but the only thing I can think of that’s wrong with a small uni is in some cases they are to maneuverable 
and there more responsive and a lot slower and harder to ideal and ride one footed etc. but if it works for you go for it my 16" has a problem with going up stairs lol because my cranks hit the steps but i like my uni because its small and very easy to jump with because it is so light but still cant wait for my 20" 
but all i can say you should be fine if it feels right just do it that seems to be the best way with unicycles also the larger the wheel the faster it will be
GOOD LUCK 
and have fun
thanks guys!