Is 24 to old to apply for the paras and will I be one of the older guys. Will I be at a disadvantage because of my age

This would give you an advantage, having a bit of life experience will help. There will be younger people but you will not be the oldest! 24 is not too old at all-go for it!!

I was 24 when I joined. It's true it can be an advantage and if you knuckle down you can progress well. The one thing I would say is that the older you are the harder it is to be at the bottom rung in training and the newbie at battalion being ordered around by anyone with rank that maybe quite a few years younger than yourself. HOWEVER, stick with it, its an experience thing, not an age thing and it soon levels out. Show maturity and professionalism and work for the promotion courses.