Earlier quoted context omitted.
>We weren't taught the alphabet until the age of about 6-7 My daughter is 1.5 years old and knows almost all of the alphabet. Is this a good thing or bad thing?
Neither good or bad. It is a clue that she probably is good at "symbolic thinking". More of this stuff to come in the near future. Just make sure she has plenty of chances to develop this (probably innate) ability. On the other hand, as she grows up, you probably should keep an eye on her and help to mitigate any shortcomings that'd eventually show up. But this is the same with all children anyway.
I've seen an approach where letter-shaped toys are handed out as toys, which provides a concrete object to associate to the letter. Children using this seem to be able to pick up the alphabet around 1 year old fairly easily.