This going to sound crazy, but I used to be absolutely terrified of needles. I've passed out twice from needle pokes, once even in class! In paramedic school, I would shake and cry when getting poked. I knew it was a necessary evil, I really wanted to be a paramedic, so I just pushed through it and eventually got over it. Now, if I tell people I have a history of passing out, that I'm afraid, they'll be more afraid than me, lol. I've even let people practice IVs on me with no issue. I got poked with a dirty needle at work and had to get a lot of blood tests regularly both checking for any HIV or hepatitis, but also to check that my liver and kidneys were OK while taking PEP (Truvada and Tivicay) for a month. They had to check me for HIV for a year post exposure. I am very used to needles now and you would never guess in a million years that I used to shake, cry, and pass out from them.
When my EMT partner first got into the field, she used to gag at anything that looked, smelled, or sounded gross. She would gag if you even coughed! I remember once putting an NPA in a patient, a snot bubble came out and oozed onto the patient a little, she grabbed a garbage can dry heaving. Now, she'll just grimace a little, say "Ew" maybe, and go on with her day.
People forget we are human too. Maybe most of you are super tough and could handle it from the get go, but I know my EMT partner and I had to work mentally hard to be able to handle this job. If you want to do it, I'll think you'll find a way to cope or overcome these things whether minor or severe.