I wouldn't take from your daughters account as that money was given to her and as unfair as it is that your son doesnt have as much people's circumstances change. My first born definitely got a lot more gift wise than my second born unfortunately. My daughter will have a lot more than my son but mainly because we've had 2.5 years on putting money into her account but that may equal out by the time he has access to the money. It might not. If you can and feel comfortable equaling it out so they have the same do so by all means (we can't so haven't). I'm sure they will appreciate the amounts they get no matter what.
So far my son has $3500 and my daughter has $100. She isn't born yet. The amount for my son has accumulated over shower, baptism and birthdays. It makes more sense for him to have more money as he's been here longer. I figure they will average out as they grow up. If it really bothers you then equal them out
This is pretty normal tbh for first and second kids. People are always less excited about the second which is a bit sad! If you have the means to even it up eventually then I would, but I wouldn't take from your other child as that's not fair either. We just reckon it'll even out eventually and if it doesn't we'll top it up closer to when we give it to them at 18.
If you want to even out the accounts, it doesn't matter where you take it from. Money is fluid and whether you do it from your own account or your daughter's account, at the end both are going to get the same. You can also top both up in the future. It is more a matter of having the resources to do so.
I normally share so they both have equal amounts in their accounts
If you have the means to equal the balances (and perhaps to invest the money / put some in a pension for them) do it, why not. If you can’t, I’d be tempted to equalise them in private and then set up a little standing order to each to keep them going until they’re older. First borns get a lot of fanfare, just the way. And people’s circumstances change over time so might not be anything in it at all. The kids will appreciate the gift in the end x