50/34 with an 11-25 cassette is perfect. It'll get you over almost anything, so that's good for you to build up fitness. If I recall, a 50/11 is bigger than a 53/12 so you're not far off top-end wise.
When I started out, I raced a whole season on a 50/34 with an 11/23 and it was fine; now I train on a 53/39 with an 11/23 and race using an 11-25 cassette - this helps get my phat ass over the climbs so I can be there at the end.
As always: it's just about riding the bike.