Identifying a body will be a stressful process for you, but you can be assured that the mortuary staff and/or undertakers will be sensitive and respectful to you and will allow you all the time you need.
I had to identify a relative after a bomb blast (NI in the seventies).
I was extremely worried about what I might see, but there was nothing at all to be worried about.
Any injuries or areas of discolouration had been dealt with by the cosmetic process, or were covered by mortuary garments.
When I presented myself at the mortuary, I was taken to an inner room where a member of staff sat down with me, and explained what to expect and what I would be asked to do.
The member of staff who attended the viewing of the body at the mortuary was kind and respectful, I was encouraged to rest for a few minutes before the actual viewing, and there was no sense of urgency or hurry to get it over with.
After the identification was over I was shown back to the room I had previously been in, and told I could rest for as long as I needed.
My advice is - don't expect too much of yourself, or try to be too stoical. If you need to rest, or need a drink of water, let them know. They are used to helping relatives and will be sympathetic.