Konbanwa!

Hajimemashite. Watashi  wa Kai desu.

Nihongo o narat benkyou shiteimasu., Yoroshiku onegaishimasu!

Good job! I hope this helps you and good luck! 

Konbanwa!

こんばんわ！

Hajimemashite watashi wa Kai desu

はじめまして　わたし　は　かい　です。　(Your name should be written in Katakana since you're not from Japan, but I am unable to write Katakana to show you.)

Nihongo o naratteimasu, yoroshiku onegaishimasu!

にほんご　を　ならっています，よとしく　おねがい　します。 (I don't think "naratteimasu" is the correct word here, but I'm not a native Japanese speaker, either so I can't be sure. There's a chance I'm wrong, too, so I guess I wouldn't worry about it.)

Think about learning Hiragana and Katakana! It's actually pretty easy. I used an app called "Human Japanese" to self teach myself Hiragana and I do believe, from what I remember, they taught a bit if not all Katakana syllables, too. There is quite a bit of reading, but I found it fun so it didn't bother me. Hope you will give it a try!