Yes, age is an issue but you're ok. Despite a recent court case, that NATS lost, anybody older than their mid forties is going to struggle and probably wont make it. Can't teach an old dog new trickes etc. Joking aside there is scientific proof to this effect. Something along the lines that if you are up to speed in your job before you are 42 or 43 (can't remember which) you are likely to be able to carry on proficiently until retirement. However if you come in completely new after that age you are unlikely to ever achieve the level of proficiency that you need to see you safely through to retirement.
This reserch is from an university and NATS tried to use it in thier defence in the court case. Nevertheless they lost becase you cant discrimante on the grounds of age. Yet another case of the courts making decisions on things they don't understand and leaving aviation a less safe place than it was before.
However in your 30's no problem. Good luck.