Hiya I'm currently a first year ODP student but transferred from adult nursing at the same uni. Before I heard of the ODP course I wanted to be a theatre nurse however my key reason for switching from nursing to ODP is the way both are trained.
In the long run ODPs and theatre nurses do the same jobs, however if you went through the nursing route you would have to do additional training at a uni after your degree e.g. on anaesthetics and additional on the job learning if you decide you want to work in theatres. If you go through the ODP route you learn everything during your degree and can hit the ground running when you graduate. Nursing students don't really have theatre placements during uni it's mostly wards/community, while ODP placements are based in theatres. I personally wasn't a fan of the wards (loved the patients and people I worked with, just the general ward environment).
If you know you want to stay in the perioperative environment and more interested in surgery take ODP, however nursing would give you more flexibility if you wanted to change speciality in later years and you'd have a wider general knowledge.