You might. Actually there's an easy way to find out. Go try it. Try playing through the first movement of one of the concertos and see if you can get through them a little bit. And then again, if you can't get through them even in the slightest, you will still be able to learn it (however, it will most likely take you a lot of time in that situation). If you can get through it a little bit, go ahead and start working on it.
Another thing: Do you know if you can perform it with an orchestra afterwards or is it just for your own pleasure. If you will be performing it with and orchestra, I wouldn't go with such hard concertos at first. Try some easier ones like late Mozart or early Beethoven. Maybe Schumann or Grieg. Playing with an orchestra is really hard. In fact, playing with more people than just yourself already is hard.
Last comment, telling us that you can play those Chopin exudes already, for me, doesn't add anything of valuable information to this post. Since every single piece will give you different problems, so will this one. Also, Chopin composed his etudes between 1829 and 1839, Rachmaninoff wrote his concertos in 1891 and 1901. Their music are very different from each other. Being able to play some Chopin etudes doesn't mean you are at a certain level of some kind. It simply means you put time into those pieces and therefore you can play them.
Anyway, give me some more information so I can give you more specific advice. And please don't take me wrong, I'm not trying to discourage or offend you. I'm not an expert myself. Just giving my own opinions and sharing the experiences that worked for me.
BW,
Marijn