I completely understand these "stirrings" of which you speak... I married my hubby 5 days after turning 24, and I would have liked to start our family right away!
We adopted our son when I was 31 and he was just over 9 months old. Because adoption has risks that can be different from biological birth, I am glad that we waited. My son, perfectly content to go to anyone who would smile at him, had sleep issues and would rage towards me. I was prepared for it because I read everything I could prior to the placement, and my maturity helped me survive without causing further emotional damage. Well... maybe that is debatable! We all carry baggage from our parents, right? heehee
Anyway, I suggest that you begin your research with attachment disorders. You'll find four different kinds of attachment issues, and it will prepare you for what makes adoption a little different from other parenting experiences. Some children are unfazed and resilient to transitions/placement, whereas other children in seemingly exact scenarios really really struggle. It's a mystery, but a lot of research exists about it. It isn't just warm fuzzy hippy science, either. Attachment impacts how the brain forms, it's neurological. I hope you will consider your research findings when considering your childcare options. Too many caregivers causes a child to resist attachment... the question is how many is too many? The science jury is still out on that one... At any rate, you also will need to understand the loss that the child experiences that is his and his alone. The Primal Wound will offer you some perspective on this.
As far as single people adopting... we know several single parent families made from adoption. Each of the parents was over the age of 30. I don't know if this was coincidence or an agency requirement. You could go the private, domestic adoption route. This would mean that the pregnant mother/family would select you after reviewing a collection of profiles. The reason a mother would pick you is not something you can really know... you just have to put yourself out there and hope that there's a good match.
You can join an adoption forum online, just to see how people cope with the paperwork process, the waiting, placements, disruptions, the bonding process, and emotional/behavior disorders, etc. I go to forums.adoption.com. Other helpful websites for me are informedadoptions.com and loveisntenough.com.
Please message me if you have any questions or want to discuss anything. I realized that I never touched on interracial or international issues... this is a whole other essay that I could write ;)