I second the research part. I have had people ask me if I would do this in the future, although I do not plan or want to have children anyhow and my life partner would not be able to carry them... so it isn't even an issue. However in the past, with a previous partner, it came up several times because she wanted children. I couldn't do it. My brother and I look so much alike, his daughters look almost exactly like I did as a child so I have no doubt the result would be appealing... however I couldn't deal with the fact of knowing that the child I was raising as mine was his in that sense. I'd rather have a stranger.
Have you considered harvesting your eggs and storing them? If you chose to have multiple children you could always use your eggs for one and her's for another. Just a thought I had at the time that may be worth considering.