3rd c.section

This might be long fair warning....My boyfriend and I are having our first child together. He has one biological child age 9 and one not biologically his age 14 both girls. I have two children ages 7 and 5 both girls. This baby makes child number 5. We financially pay for all children's birthdays dances Halloween Christmas valentines back to school clothing and supplies everything. Due to baby not letting us see between the legs we don't know the gender of this baby and it being my 3rd c.section I've opted for female sterilization during surgery. Well here's the thing I'm second guessing if it's really what I want I know I didn't want to risk more then 3 c.sections and we have enough children already but my hearts set on having a son and if this baby is another girl then I won't be able to have one ever. Its seems like a simple choice at first but now its sinking in that I won't be able to try even if I wanted also I'm 23 years old...I know realistically I shouldn't even think about more children but I dont want to give up a chance to try for a son and tech I will only have 3 biological children after this one and 4 dosnt sound as bad as 6 kids lol not to mention his oldest wants nothing to with me and his youngest is only here every other week...idk I'm not sure if female sterilization is really what I want. If this baby is a boy then I wouldn't think about it I would go through with it I just want to be able to have a son. I know of this baby is a boy or girl I will most likely go through with it due to the fact it's the 3rd one and we already have enough children it just makes me sad thinking I might not get my not I've dreamed of....I'm too conflicted with what I want to what I should do...and he's not willing to have surgery I can't even get him to get a primary Dr. Let alone think about a operation on his genitals lol.