My own opinion is start Kanji as early as possible, your going to see it everywhere, so you may aswell get used to it
Also the kanji will help you differentiate between words which are pronounced the same but have different meaning, for example.
代える - To replace/substitute
帰る - To return
変える - To change
All are pronounced かえる
And even if you can't write them all out at least you will be able to read them when you see them, which is miles better than not being able to read any at all.