I need help figuring out which birth control method or pill I should use?

I just had my baby 14 days ago, and I wasn't planing on having kids till I was older. But I still love her so much! Ok well my point is I took the pill every day and used it right but it faled on me. My doctor told me it only works 90% to prevent pregnacy. Now I'm gonna get mirena which works 99%, so I think that's better for you. You only use it once and last 5 years! You don't have to remember to take it every day.