Can doctors refuse to tie/cut your tubes?

Crystal
I will be turning 24 this August. This is my second baby and I am certain I do not want anymore. Not only has this pregnancy been extremely rough on me I see how much work three kids are and I just don't want any more than two. I want to talk to my doctor about cutting my tubes but being only 24 and with 2 kids I'm worried they're going to give me a hard time saying I'm young blah blah blah and tht I only have two kids. My sister was 24 when she got her tubes tied she was pregnant with her 3rd and they really got at her about it.. I feel tht if it's what I want, they shouldn't refuse me, my body my life. I'm just nervous to talk to my doctor about it.