Can i give you some feedback?
First of all, it looked really...boring...you should add some ,,aesthetics", some optical improvement.
Then, add checkpoints. Beds, Cmdblocks, anything.
The dificulty was okay. The length was okay, too, as you said it is short.
The ravine part was very confusing with all the buttons...but okay.
The water maze was very good, but you don't need that many air parts with a respiration helmet :)
The desert part was...well, i never liked cacti jumps as they're annoying, but the opinion of others could be different.
The fight part wasn't good. It should be more dungeon-like, with systematic monster killing, not just a ,,go in and 100 monsters spawn and you just go in the corner and spam mouse klicks". As i died in there, i had to start from beginning, so Checkpoints! Please, Please, Please!
The timing part was challenging, but not too hard, so it was fine! :)

Basically there weren't any things where I said ,,This is very very good" but the map also isn't ,,very very bad". As its your first map, i hope you consider my criticsm and I think you can do better next time ^^