Someone else should jump in (I've only been doing ERP for a couple of months) but I think it's fine if you acknowledge or realize that it's ok and even to tell yourself that. Where it becomes problematic is if you need to say "this is ocd and I'm actually ok" as a way to avoid/push away the obsessions. Put another way, if you're saying it do sooth yourself and to counteract whatever you're obsessing about then that's bad. If you notice, you're repeating it over and over and that you feel an urge to say it, then saying it is just validating the obsession and making it worse.
Without acknowledging or telling myself that it’s ocd or it doesn’t mean anything (“it’s just a thought”) then it’s hard to understand how to let it be there without becoming fused or identified with the thought itself and basically just continuing the intrusive thought pattern
So the best way to deal with in intrusive thought is to acknowledge it and say "This is an intrusive thought." Then completely ignore it. Don't try to reason, argue with, or disprove the thought. Your anxiety will go crazy at first, but then it will peak and decline.