I personally would prefere to use AI for safety of mare and stallion. There is obviously a risk of losing mare and foal which is top of priorities to consider. But it is a massive achievement and satisfaction to have both mare and foal safely here and wow what a proud feeling!!!!!!!!!!
I would think at 5 years old your mare wouldnt have a major problem with fertility but no one could say until you try. Usually older mares are more difficult to get in foal.
We are very lucky as we have a local stud with an AI technician, just down the road and I take my mares for scanning and AI without having to ever leave them anywhere else. I certainly wouldnt be happy sending my mare to stud and leaving her, so in that case I would only use AI and if I use a natural service, we scan to find the correct day, I travel the mare cover her then bring it home. In general this has I find been 100% successful, only time I would count that out would be when the mare has had a problem, this being with two maiden mares, which both have been started one of which foaled last year the other being due this year!!!!
I must admit I have had two occasions where the stallion owners have brought the stallions to me, in that case I have met them with my mare at the stud so my stud owners would supervise, and one other occasion the stud owner came to our yard to supervise a covering. This is only as I completely trust the stud owner and his expertise and this I believe is where you need to be, whether it be a vet or a stud owner/AI Technician you need to trust and find out their success rate.
I foal my mares at home, although they are taken to stud for AI due to safety for the handlers etc, as they are set up with stocks to put the mares in thus cuts the risks of kicks etc to the technicians and vets who scan, but I also know the stud is at hand if I had a problem with a foaling and would come night or day. You need to know someone is there at the end of a phone if you have a problem.
You need to gain as much knowledge as possible before your foaling and the most important thing, if at all possible, is to be there to limit a problem happening and supervise so you are able to call for assistance if needed. Get to know all the signs for the foaling night and just keep checking your mare at very regular intervals days and night!!!!!!
Good luck and I hope you find the right stallion and have a successful pregnancy!!!!!!!