Unfortunately – for some reason – introducing two rabbits is a bit tough – who would have guessed?
Since your bun is still fairly young, I think that introducing them would be easier than two adults. What I would recommend is bringing your bunny back to where you purchased it from, and introduce the two bunnies to see which one gets along with your bun the best. In my experience, young bunnies are much easier to introduce than older bunnies – I bonded a very young rabbit a couple months ago to another young rabbit and they instantly bonded – it was so sweet! So I think your best chances of getting a companion bun is right now, so I would spend just a little extra time picking out the bunny that gets along with yours best.
Regarding the spaying and neutering – the reason that it is soo important to do this is because buns can get pregnant as soon as they hit three months which is really unhealthy for the female rabbit to get pregnant that young. Its so likely, that I probably shouldn’t even say your female CAN get pregnant, but that your female WILL get pregnant as soon as she and her companion hit sexual maturity. Because it is so easy to not really know exactly when your bunnies hit their sexual maturity, as well as because it is SO frequent that male buns turn out to be females and vice versa – its really much safer to keep two buns separate until they are spayed and neutered.
I do hope that you consider a companion for your bunny though – they are really very happy in pairs, and it would be very nice for your bunny to get to have a sibling around
(though the sibling thing doesn’t stop the males and females from mating…) I think you have the best chances right now of making a great bunny pair!