Assessment worries

I filled in and returned the screening questionnaires and have just had the appointment through for the formal diagnostic assessment. It's in 2 weeks - Tuesday 5th June (I went private after a year on the nhs waiting list)

Stupid thing is I am now worrying about it. I didn't realise I am probably autistic until just over a year ago. Up until then I just thought I was a bit thick or childish. I could never work out why I couldn't understand people/life, why I hate social gatherings, and why noises lights a smell affect me so much as well as a ton of other things like why I failed school etc.

Since a close friend of mine (who has 2 autistic sons) told me that she thought I may be autistic and encouraged me to get a referral I have felt so much more at peace with myself. I know why my moods change so quickly and why I can become distressed over small things, and because I know the reason behind it I can deal with it a lot better. I know how to avoid a meltdown (Which I used to think was a sudden episode relating to depression because I thought I was mentally unstable, brought on by other people being inconsiderate or mean. In fact my life has been SO much easier. Now I GET it, and so does my longsuffering husband!

Now I'm at the point, though, of 'this is it - I'll know for sure soon' I am nervous that they'll say I'm not autistic, that they'll just say I'm an attention seeker, or an anxious depressive.

Did anyone else feel like this? Worries about 'what if I'm not autistic'

Plus, it's a 3 hour one-off appointment  (with a diagnosis at the end) and I have absolutely no idea what will happen so I can't prepare  (Can anyone shed any light on what may happen?) - I'm useless if they put me on the spot with a question. I always think afterwards 'why didn't I say that'