Sentence translation help (「そう長く生きていない」「まだここに来て日の浅い」)

I was having trouble translating this sentence, specifically the last part:

だが、そう長く生きていないとはいえ、人生の半分以上をここで暮らし、また言葉を操る『言ノ葉使い』である僕には彼がまだここに来て日の浅い使用人であることが分かった。

I understand that 「長く生きていないとはいえ」 means something along the lines of ‘although I haven’t lived that long’, however I’m not sure about the function of ‘そう’ in that sentence. I translated the next part as ‘living here for over half my life’, and the next one is about him being able to use ‘Kotonoha’ to manipulate words. However the last part confuses me a bit, specifically the use of ‘まだ’, and also the use of te-form in ‘来て日’.

Also ‘浅い’ usually translates to ‘shallow’, but can it be translated to ‘young’ in this context?