EoinC said:Macca - I think it's not so much a case of having fun every time you hop on a bike, as it is overall enjoying what you are doing (that is, making sure it doesn't get to a stage where you really don't like it each time you hop on the bike).
I think Roadie Scum is right in that, what you do as a 14 year old won't have a huge amount to do with how you ride as an adult other than that you will have picked up some bike-handling skills and you will know how to race. That doesn't mean there is anything wrong with it (both of those plusses are important), but I'm not so sure that the body you build at 14 is too closely related to the body you'll have in your mid to late 20's.
As Roadie Scum pointed out, there are a lot of mighty fine Senior riders who never raced as Juniors. There are also a lot of mighty fine Junior riders who have given it away before they got to become mighty fine Senior riders. As long as you can maintain a degree of enjoying doing what you are doing, you should be OK. You are exhibiting a lot of dedication and self-discipline for your age, which is a definite advantage in road racing. In some ways these are more important than physical prowess.
Keep it spinning, Macca, but keep an eye on yourself to see whether there are moments of pleasure in there - it certainly helps.
You will pick up valuable tactics and bike handling skills at a volume much less than 450km a week. Note that I still think it's fine to race and ride, just not to pretend that a 14 year old can handle what a top level adult amateur does in terms of training. Finding a good mentor/coach who knows about juniors will really help with learning about tactics and skills and keeping the volume at a reasonable and enjoyable level.
Definitely keep it spinning, I don't mean to discourage you there.