I think you should do it for however long you like & if you are both comfortable...
Although bearing this in mind I had a good friend & her boyfriend 19 yrs at the time was a twin & one day we went to his place to pick him up & his Mum was breast feeding her 7 yr old son...
He would eat lunch etc at school, drink water, but she woulkd express during the day & freeze it, but Breast feed him at night & first thing in morning... Except on W/ends he either had boob or expressed milk in a cup! We happened to be there at 9am (going away I think) on a Sat morning & I have to say it was really weird to see coz he was walking, talking, reading, riding a bike etc, but would walk up to Mum have a suck & just help himself! We were both pretty put off!

If I could have brestfed maddy I would have for atleast a year, probably not much longer than that tho, but as it was she would not take a bottle after 10 months so drank cows milk from cups!

With this one I will b/feed (if it works) until I go back to work..

But I say if your fine, bub's is fine & your both coimfortable with it, ignore the looks/words etc!!! Just do it!