The fringe events are just that. Many have been running for decades and each has evolved its own character and funny little ways. There's (usually) no intention to exclude newcomers but these aren't random groups of strangers, they are often reunions of people who have been going there for many years and who may also know one another from other festivals. It's inevitable that a newcomer of any age can feel a bit out of place and may find it cliquey. You need a fine balance of tact and assertiveness to make your presence felt without treading on the old-timers' toes. If you can manage that then most sessions will make you welcome, and before long you'll be accepted as one of the regulars. However there are lots of sessions, and if one doesn't feel right for you then look for another.

Also bear in mind that all festivals are different, and one person's favourite may not be another's. Personally I prefer Sidmouth to Whitby, but others I know prefer Whitby to Sidmouth. In many ways they are quite similar and the differences and reasons for preferring one to the other are fairly intangible and largely come down to atmosphere and 'feel'. Just because your friends are enthusiastic about Sidmouth, doesn't mean it's right for you. It would be worth trying some other festivals of a similar nature.