Advanced toddler? Is this mad?

[ItsOkayItsJustMyBreath]

Have NCed for this as it feels a of a cringy thing to ask

Ds is 21 months and I am beginning to think that he may be showing signs of being advanced. By this I mean he knows the alphabet both names of the letters and their sounds, he can count to 12 and knows other numbers such as 20, 100, 150 but can only count objects up to 12 iyswim. He talks a lot and uses the correct verb tenses and has a very wide vocabulary. He is incredibly inquisitive, he genuinely wants to 'learn' and finds it interesting.
Today he 'sounded out/ read' his first word, "sky". It was unprompted and in the middle of the town centre.

My question is, is this normal development? Even if it is advanced it doesn't necessarily mean that he will always be advanced does it?

Sorry to be so pfb, my DM is getting very excited at the prospect of another genius in the family (the others being my DB and my biological father) and I'm not sure what to say to her as it is exciting but everyone thinks their child is brilliant don't they?

[rhetorician]

madwoman that's pretty dreadful. I'm sorry you had to go through that.

[anothercuppaplease]

Yes madwoman, DS is on the special needs register because of his speech disorder, but he is also very advanced in other areas. He started to read as he started to speak (at 3, he read Koko as in the train in Chuggington). As a baby, he was always putting things in order of colour, shape (without showing any other signs of asperger or autism), he could do puzzles from very young, he would point at numbers in books (page numbers) instead of pointing to the images, he would point at various shapes (for example, he walking down the road he would point at circular manhole covers on the pavment, making circles with his hands, same with squares, triangles,e tc) he could point at the correct number from 1 to 10 by 12 months old, he could point at the correct letters (phonetics) from about 14 months old. But he couldn't say byebye, or mum before he was 3 years old.

As it turns out he is now 5, in year 1, and he is exceptionally good at maths (as in, he knows that 0.25 is the same as a quarter) and he understands percentages. He is learning the piano 'by himself' we got him a book and he is learning from that, he has exceptional memory, learning his times tables, etc. He can spell words such as 'annoying' (so his teacher tells me).

Anyway, I suppose that what I'm trying to say is that some children who speak late, and who have reached other milestones later, are not necessarely behind in learning. I know people have looked funny because he can't say 'cold' clearly, or most vowels for that matter, but he will ask questions such as 'what is the smallest negative number' and know what's 50 X 50.

[ItsOkayItsJustMyBreath]

Ha ha, just saw this on the daily fail. Do you think they're spying on us again?