It's already late so i'm goig to sllep now. Mou zuibun osoinode, ima watashi wa nemasu.

もうおそいじかん(遅い時間)なので、ちょうどねよう(寝よう)としていたところです。 mou osoi jikan nanode, tyoudo neyouto siteita tokoro desu.

I think "Ima wa osoi desu." (not wrong) "mou(already) osoi (jikann) desu."(currently) ”watashi ga nette imasu” mean " I'm asleep now." "i am going to sleep now" is "ima neyouto siteiru tokoro desu."

もう遅いので寝ます。 Mou osoi node nemasu.