sis, your child is 12 yo na, at least nearing 18. by 18 she is considered to be an adult already, and could manage her affairs. as to your question that you would want her to be at your side, in case of your early demise, pwede naman ngayon pa lang, you can make any written bilin, whether notarized or not, stating that in case something happens to you, that your parents/other relative/friend will be the executor/administrator of the properties left to your child, para madali rin mag-claim ng benefits and insurance for a minor child. hope that helps.
super off-topic. haha.