the younger the better, avoid 2/3yr old senegals, reason there are so many in classified is because, those are there tantrum/coming of age yrs and they will be a hand full! also older sene's that have not been so******ed properly are harder to work with, so could be another reason for being 2/3
younger bird will be more accepting of your daughter and dog
but with saying that about the 2/3 yr old sene's mine was 2 when we got her, in season an a force to be reaconed with, but i will happily say now she has settled into our family life. she is happy step up for us (though i only ask her to for me when i know she won't bite lol) and yours will hit 2 and you will go through a naughty stage, but as the birds grown up with the dog and your daughter, may not be as nippy and your daughter will know how to handle/avoid her when the bird gets that way out.
also at the end of this yr nut's season will come about again and i will see what will happen then lol
she was good with my step daughters little girl who is 4, and i gave her very clear instructions on not to touch her, even if she landed on her, though her bites are mostly nips, it can be very off putting for a child, especially when nut nipped her lip for the crumbs, or swooped low over asha's head because when she did asha stopped jabbering an was quiet for about 2mins, she also took to landing on top of asha's head a few times, for longer periods of quiet, she only flew to asha's head when she went onto full jabber mode, but for the most part she watched her from top of her cage, but only with interest
funny thing is when i look at how the feathers lay on nut's face, i can tell when she is plotting something, especially if there is a naked toe about, why cos she likes our reactions when she gets 1, she neveer bites hard, she just hangs onto it lol
one thing i did notice, nut bonded slow with my son, and for a time he was her fav chew toy, mostly as he won't leave her be, but now he can pick her up, she'll step up for him, and even sit on his shoulder while i mist her, he gets misted to lol but she really does not like the mister! thats a lot more then what she does for me now, even though at the start i could do all those things with her. i spend most time with her, then my son and lastly my man
she is a great source of fun, when she is in the mood, like chasing toes, burrowing under blankets for toes, taking plaster off the walls, her fav thing to do is to nip my son on alternate ears, while his on his x-box, he lets her as they really are gentle
nut is flighted, so that is something you will have to decide on, weather to keep your bird clipped or not
personally because of how nut has accepted and interacts with every1 in the family, and even the none fav person, mans the fav and 50/50 between me and my son, though i think my son will be over takin me in the next fav person list, i'd say sene
but what ever bird you get, will be like raising a child, do it right for a better outcome, so even older birds that have been raised right will adjust easily into a new life, your daughter may have to take it very slow with the bird, but she needs to be involved, to stop bird from only allowin you to handle it, even when the birds a little naughty, so any bird you decide on, you should both visit a few times, see what its routine is, but with saying that you could come see my nut, lol and you will love her as she likes the men, and she will be all over you, demanding head scrathes etc, she will also check out your daughter, by landing on her, taking treats from her etc,
but i know when you get her to your house, there will be a period where she will be nippy and rather angry and not be the bird you came to see for a little bit till she settles into your family life lol