My DS1 is 20 now and was diagnosed with GDD at 12months. Ofcourse every child is different but I can give you a perspective from our experience.
he said his first word at 2
at about 18 months his sleep became extremely erratic, we were sleep deprived (to the point of absolute exhaustion) until he was about 14
we then managed to get him to stay in his room until 5:30, then a couple of years later until 6.
it took me years to potty train him, we were still washing poo accidents until 10. After that he continued to have accidents but less frequent. Now at 20 hardly ever.
he was diagnosed with ADHD and takes medication
he has a severe speech disorder but can communicate, and is very chatty!
we tried mainstream which kind of worked for reception although we had to collect him on many occasions due behaviour issues, in year 1 it became clear mainstream was not the right environment and we were lucky to get him into a fantastic special school. For secondary he also went to a special school. Both fabulous places with people who knew how to deal with his needs. He loved school! Came on leaps.
after 2 years of helping him on a balance bike and physically showing him how to move his legs (my back really suffered!) he finally learnt how to ride a bike. This is a great thing to do as he is unable to participate in many sports due to motor skill difficulties
I took him horse back riding (for the disabled) from around 3 years old, really good activity as well for brain development
swimming once a week every week
lots and lots of stimulation, I spent a fortune on all sorts of therapy, don’t regret it!
for many years we walked on eggshells due to his behaviour becoming more and more threatening, I think it might have been hormones. Since around 18 this is so much better and he is able to control his emotions a lot more.
really important that you find a course to teach how how to deal with neurodivergent children, the parenting rules for other children simply do not work
finally, he is an absolute joy! We adore him and brings so much love to our lives. He helped me learn all about unconditional love and also to see how strong I am. He is a beautiful soul.
I’ve had support of a fantastic very involved DH, we understood that when tired we needed space.