She is tiny, but Tonks are on the smaller side and being female that's understandable. I'd let her explore for maybe no more then an hour supervised, then confine her to her room. We got Charlie at 4 months old. He was supervised with exploring for about a month and confined when we couldn't watch him.
He was between 5-6 months before he was allowed total freedom of the house and basement.
He was between 5-6 months before he was allowed total freedom of the house and basement.