having my tubes tied

meg
I meet with a doctor about tying my tubes. I'm 26 and this is my second child I will be having via c section. Due to my medical history with my back I can not do another pregnancy. So I'm going to have my tubes tied. What are some questions I should ask my doctor about the procedure? Something major I should discuss? Just trying to cover all my bases so I know exactly what I'm in for. Also my other obgyn has been trying to talk me out of it cause I'm young. I'm absolutely sure I want to do this. What was some other moms experiences with fighting for getting tubes tied? 
UPDATE: I had my appointment today. Of course they said no again. We discussed my medical history with my back. The doctor said that they still weren't going to do it. I couldn't help myself I started crying. I do not want anymore kids. I don't want to be pregnant again. I've given this a lot of thought and dicussed it with my husband a lot. I'm 100% sure I want this. I don't want to go on birth control. That's how I got pregnant with my first. For me this is the best thing for me. I just don't understand why they keep saying no.