A novice only session is a good idea if available- not to be offputting but in my experience the slow group is sometimes the worst place, not because of the slow/inexperienced riders as you might think but because of the bellends. There’s always at least one dick who should be in inters or fast but who just likes overtaking people. Some trackdays are better at dealing with this than others, knockhill couldn’t care less. Racer in novice? By all means, go ahead.
It can be great though, especially if you’re with friends (though, I always seemed to meet people fast even when riding alone). And on a positive-negative front, if you’re relying on riding home, take a spare brake and clutch lever at least, these are good to have regardless but a slow-speed spill could cause you a lot of hassle.