I've now had around 20 LD's since I started and I am just now getting to the point where I can plan what I want to do before hand.
I think if you feel the need to have a goal in your LD's you could start with something not too specific. Like "I'm going to make my lucid dream last as long as possible". Then next time say "I'm going to make my next lucid dream last even longer than the last time".
There's no need to have an ultra specific goal like - I'm going to go visit my dead uncle Harry and ask him why he ran over my tricycle when I was 5 -

You say you just want to explore, than make that your goal.

And if you are worried about a lack of conviction. Just focus your intent on becoming lucid, on realizing you are dreaming. That should be your number one goal.