I took the liberty of doing my own math.
When Jade and Mia were born Adam was 8 years old, Jade left her family when she was 16 which leaves Adam with an age of 24 when Jade left, it has been 8 years since then leaving us with Jade being 24 and Adam 32 years old at present, as Bella says, Ashley and Andy is the same age as Jade when she left which is 16, so the twins when Adam was 16 and Jade was 8, then the twins would be 8 when Jade left.
Which leaves us with this result:
Adam: 32
Jade: 24
Ash and Andy: 16