I think that it is important to answer this with the Word of God. Does the Bible say that there is a limit on how big or small a fellowship of Christians should be in a person's home? Obviously a comfortable amount would be best in my experience of living life. I went to a small school and to a large school and can tell that my education was better in the smaller school. This is why studies have shown that smaller schools provide better education because the teacher can give more attention to each student. If the number is too large, they cannot give the time needed for each person. I would say that a person should pray about it and then seek the Scriptures. Even if the Bible does not talk about this topic directly, it most certainly talks about this topic in an indirect way.
All Scripture is profitable for doctrine so that the man (or woman) of God may be perfect into every good work (2 Timothy 3:16-17).
I hope this helps, and may God bless you and your family in the Lord this fine day.