jnmum - first question - are you white ? if not you have a lot more options as many children in care are of mixed heritage .
dont worry about your age - you are not too old
as a rough guess i would expect the process to take about two years, once you have found an agency to assess you. i would be surprised if you can find an agency willing to assess you for a pre school child, unless you can take a child with SN
my advice would be to find out as much as you can about school aged children in care are likely to have. then you need to think very seriously about how these would impact on your DD and your family.
who would watch a child when you are at work? during the school holidays? if you have a child with challenging behaviour, most child minders or out of school clubs will not take them. what if the child is excluded from school? if you are a foster carer then SW will step in. if you are an adoptive parent its your problem
what if you get a child who doesn't like parties, clubs, family visits or holidays? how will that affect your DD? do you have someone else who can take her to these while you stay at home with your other child?
if your new child is violent, how will you ensure the safety of your DD and neighbouring children?
what if you have a child who has been sexually abused? can you cope with that?
i am not trying to put you off, just to get you to be realistic about the IMPACT that adopting such a child will have on your family. Its one thing to say
"oh i understand that they may be have behavioural problems or have been abused or neglected"
it quite another to appreciate the affect that such experiences will have on a child and subsequently on you as their parent