Jersey/ Guernsey Holiday recommendations with 3yo

[Tillyboo]

We thought we might try one of these as we haven't visited either yet.
Would either or both be suitable for a 3 yo dd ? Or is it full of older/ retired holiday makers ?
What's to do? Where to stay ? Tips and advice would be great.
What's the weather like ?
Thanks

jersey is great, we hired bikes and went everywhere, you can get bikes with little 'houses' on the back which worked a treat for us! the gerald durrel zoo was brilliant but its hard work and all up hill to pedal! it was worth the hard work though and dd loved it. theres a restauarnt in st hellier called the 'salty dog' which is one of the best restaurants ive ever been to. there are loads of litle islands off the coast with little castles etc which are ok too. we went for a weekend in may and it was warm, tshirt weather but not hot, warm enough to eat a lot of fab jersey icecream though!! theres quite a lot to do for kids and it is really beautiful but not cheap to be honest! hope you enjoy it if you go.

Jersey is afab place to enjoy the outdoors and the simple pleasures. walking, sandcastles, good ice cream etc. we lived there for 2.5 years, there is alovely park, the zoo is fab, plenty of beaches and rock pools. weather, as a rule is generally milder than UK.
I'd stay St. helier/St. aubins and then you can't realy go wrong. Or st. berlades bay