Hopeful adoptive parent

Like many, my husband and I have not been able to conceive. However, with or without biological children, adoption has been close to my heart because my mother was adopted (through private / direct adoption). So it has always been engrained in me to be open to adoption.I really want to get started and adopt children, but don't know where to begin. First things first, my husband and I are middle / working class, so adoption expenses are daunting. Secondly, I have had some recent medical issues, so we are hoping that will not put us out of the running as a prospective adoptive parents.We are open to adopting up to toddler age, but we are still fairly young (30yrs old, husband 35yrs old), so we are not sure about much older than that age.It may be worth mentioning that we live in Illinois.