I'd join sooner rather than later. A BIRD IN THE HAND IS WORTH TWO IN THE BUSH.
I knew of someone who was offered a BA sponsorship ten or so years ago when BA was good with final salary pensions etc. His parents advised against it and made him continue with another Uni degree. He got the degree and still wanted to fly so his parents ended up paying for his CPL!!
There aren't thet many opportunities out there for new hire pilots. Also if it's you (35) against another (25) who would 'the company' think is easier to train?