I did hunters for 5 years and when we moved I couldn't keep going to that barn. My hunters coach recommended a trainer closer to when I lived and she did primarily eventing herself so I got right into it.
It is definitely important to find a trainer who is active in the eventing world. My trainer would saddle up her horse and we'd ride together most of the time- every jump I did she would do first. Every dressage test I did she would do first. It was great to not only be told what to do but be shown at the exact same time. Plus she was active herself in competing so she was familiar with other farms, other riders/trainers, judges, rules, etc.