I used an anonymous clinical donor myself. I didn't even have the option of a family member or anyone I knew. Plus DH wanted completely anonymous. But I personally like the idea of knowing the donor.
Since you are very interested in your friend I think it would be fine to go ahead and ask her now. Realizing once the cat is out of the bag and you start telling people you are interested in using DE that she may tell other people and it could open a can of worms. But if you plan to be open about it then it is fine. But it is likely she may then ask for advice from other people as to whether or not she should donate.
Usually women find a clinic first and then look for a donor. So you could ask your friend while at the same time investigate clinics you are interested in both near you and near her. But there are lots of clinic options and you may decide you want to travel for a clinic that is not close to ether one of you. Since you want to know the donor I would start getting recommendations for egg donor agencies as well and then get passwords to their donor databases. Then you can start looking at hundreds of donors online and it will give you ideas of what criteria you are looking for in a donor. Many donors listed through agencies are willing to have open contact with you. But using an agency is the most expensive way to go. And you want to find a reputable agency.
The least expensive and easiest is selecting a clinic with a large anonymous donor pool. Those donors have already been screened by the clinic and meet their requirements as a good candidate. And most are previous donors. They have already been tested for antral follicle count, FSH level, medical history background, psychological testing, etc. But if you want a clinic donor that is not anonymous and willing to meet you then you will need to find a clinic that is willing to do that.
If you ask your friend and she is interested in being a donor then you will need to find a clinic and do whatever testing they require for her to be your donor. You will also need to hire an attorney to create some sort of legal contract with the donor. And if you decide you want to pay for a guaranteed refund plan then your donor will also have to meet those requirements or you won't be able to have her be your donor with a guaranteed refund plan.
So there are tons of things to look at and consider and it may take a while to look at all these options. But taking time is good as it allows you to get more comfortable with all of it.