Hi Rosaly,
Denzil, my 14 month old Yorkie, was very reluctant to go out when he was younger - I think he was a bit scared of the world to be honest! I persevered taking him a little further everyday. Now he loves his walkies and we have to spell the word rather than say it as he goes mad! We go for a good hours walk everyday and he hates coming home, I virtually have to drag him along.
Do you use a lead or a harness? Denzil has a Puppia soft harness which he loves (but also has a collar with name tag) Not that I am an expert, but I'm wondering if he has a collar he may prefer the security of a harness.
Good luck and keep us posted.
Tracy and Denzil