I do think that is a brilliant post pandarific and I agree with what you've written. I totally object to the assertion that it is selfish to have a child in this way but that all the other ways of having children (many of them NOT thought through or ideal at all) are not selfish.
However, I do think it is misguided not to talk through the possibility that your child may have issues about their conception/lack of parent and to decide how you may handle that or indeed if you can handle that. My own experience of using a known donor is that it has been a largely very easy, positive experience for myself and my Dd. At the time I had her some people thought what I was doing was wrong and very weird but I felt very strongly that it was not and now that Dd is here (she's 11 now) they never mention her conception at all.
I had the opportunity to try to have a sibling for Dd but this time with an anonymous donor. After much consideration I decided that I was not comfortable with doing this. I'm not saying there is anything wrong in anyone else doing this I'm just saying I decided it wasn't for me. DW didn't really "get" why I couldn't do this because she came from a very toxic family and says she would have welcomed not knowing her own father! So....different veiwpoints based on our own experiences!
The family I know who have children from an anonymous donor have always found it rather irritating that their children are interested in finding out more about the donor. They believe, and I'm not saying this isn't true, that they ought to be enough for their kids, they have 2 great parents, why do they need to know about their father. That is not how the children feel. Well they do in one way but they are conflicted because they both feel tormented by the idea that their "father" is out there somewhere. I really think if they actually engaged with the children a bit more and let them express their feelings about the donor it might be a bit easier for everyone but they are sort of afraid to and don't understand the children's desire for information. Also they say they feel guilty because they can't provide that info. That said there is the donor sibling registry now where children can find siblings and possibly their donor in an indirect way so maybe these children will do that in the future.
OP, I really would say if you feel ready to be a mum then go for it. It sounds as if you would be brilliant at it. I'm just saying it is no bad thing to think these issues through and decide how you are going to cope with them. They may not be a problem at all for you and your future child certainly these issues have been very much in the background for my family, we are incredibly happy and I'm sure you would be too.