Not enough information to judge. I wouldn't condemn anyone as 'too old', particularly as you are a spring chicken compared to me. What I would say is:-
Do you have 3 A levels (2 year course)?
A degree (3 year course)?
Because that's what you need to get onto a PGCE to train as a teacher. Obviously, if you don't currently have a degree you are looking at £9,000 a year tuition fees, etc so it's an expensive thing to do nowadays. Your TA experience should help greatly, as I understand Primary PGCEs are very competitive to get onto, but my advice would be to think carefully about how long it will take you to qualify and whether you are prepared to put the hours in.
Teaching is pretty hideous these days. I'm a Secondary HoD and work around 60 hours a week in term time, sometimes more.
Today, as an example I was out the house by 7.00am, taught 5 lessons, ran a lunch club, ran an hour after school GCSE intervention class, got home at 6.00pm and have since spent 3 hours marking A Level essays. I'm buggered now; spending half an hour on Mumsnet and going to bed! I'm told Primary can be worse 