I used to be a foster carer - I didn't have my own children and have since resigned after adopting a LO we cared for.
I know of many people who DO foster with their own BC, perhaps though not as young as yours, who will say it has been a huge plus in their kids lives.
Personally for me, I would not foster if I had such a young child at home.
The amount of running around (health reviews, contacts, LAC reviews) will have an impact on your life and your LO... they would look to place young children with you (they too like a FC to be the youngest in the family) - so you'd be looking at babies, and these apparently (due to concurrency planning in adoption) are few and far between.
Are you prepared to have your child looked after by other people so that you can attend training, meetings, contact, health reviews.
I really don't mean to sound negative (altho I am biased with such a young child at home), but I think you really need to be aware of the huge impact it will have on your "family" life.
Good luck whatever you decide and feel free to pm me to ask anything else