Hi Mia and welcome - and Wahey! you got an allotment~! We've had ours for a year and I can totally relate to the dreaming about it thing. I had a fever a while back and was hallucinating about pricking out seedlings.
Whereabouts are you? It makes a difference as to what you can plant out, as does whether you are in a city site or out in the country.
Have fun.