Child is grade F student upon age up?

Normal human sim, the toddler was very hungry and had a very low attention when I did so because for a while the option to add birthday candles wouldn't appear (probably for a few in game hours) and there are other toddlers in the household so the carers had to attend to them. I got her grandmother to make another cake and by then the option to put candles on finally appeared (on the previous cake I had made too). I put the cake on a table and got grandmother to help her blow out candles, but it wasn't working because it was on a coffee table, which I didn't realise, so her needs just kept going down whilst I paid attention to the other toddlers. Eventually I figured out what the problem was and put the cake on a kitchen counter and aged her up immediately. Now that I think about it, this might have happened because I was close to having my toddler taken away or something.

Edit: Her mood was most likely sad or even very sad because her needs were low.