However, she said there were "many, many other questions" about Brexit and there was "still a lot to do".
The UK proposal was unveiled by Prime Minister Theresa May at an EU summit in Brussels on Thursday.
It would grant EU migrants who had lived in the UK for five years a new "UK settled status".
That would allow them to stay in the country and access health, education and other benefits.
The plan would affect 3.2 million EU citizens now living in the UK.