You're worrying about nothing. It is well recognized that med students can seriously consider multiple specialties before finally deciding.
For the record, if you don't go the combined child psych residency route I mentioned above, I would strongly encourage you to TRY and decide between peds and psych before you submit your ERAS. You're only halfway through 3rd year, you still have plenty of time as of now to make your decision, so you should by no means have already resigned yourself to applying to both specialties. You're going to have to make a decision eventually when you make your rank list, so you may as well do it before you waste a ton of time and money on applying to a specialty that you ultimately don't even rank.
There are of course people every year who apply to multiple specialties who think they have a good reason for doing so, but I believe pretty strongly that it is always a bad idea if it can be avoided.