Translation:Is my friend pretty?
I agree, and I would think that is even more accurate than Is she pretty, which I would translate by "我的朋友漂亮吗？”
The V not V pattern already constitutes a question, using 嗎 in addition would be redundant.
the ＇漂亮不漂亮＇already serves as a question. it's like "my friend is pretty or not pretty?".