你好!

认识你真好,我叫莎拉。我是美国人和想学中文。

你好吗？

你好。。。

认识你真好
a bit weird here. i know what u wanna express, smth like "so good to meet u here" but here we'd better to say "很高心认识你"

我叫莎啦
"啦" is an interjection in  chinese and probably not used in a transliteration name and instead, "拉" when the syllables r la / ra / lla / rah etc

我是美国人和想学中文。
it's alright in english that we'd say "i'm a american and wanna learn chinese"  but we always omit this conjunction

你号(好)吗？
a wrong character, anyway )))

hope this will help. not bad actually...lookee, at least all of us could understand what u mean, right? ))))

你好。。。

很高兴认识你。我叫莎拉。我是一个想学中文的美国人。

你好吗？

你好。。。吗？

认识你真好。，我叫莎啦拉。我是美国人和，我想学中文。

你号吗？

Nice to meet you!

In China, greetings are before what you want to say.

Hope to be language friends with you!

你好。。。

认识你真好。我叫莎拉。我是美国人很想学中文。

你好吗？