Here is my male boa at 2,5 years old (he's over 2200g now). I know it's not a female but my friend has a female at same age and she's a bit smaller (he's not feeding her as much as I do - I feed mine with 150g rat each week).
On hands to see the size:


He has never refused a single meal - even in shed he eats no problems. I will see how much longer I will feed him that, but for now I think it's alright (I mean meal size as far as how often he gets it ;p). But probably after he reaches 3000g I might start feeding him every 10 days or even every 14 days etc.