I saw a cute dog walking towards me and then I realized it was my dog.
I saw a really cute dog walking down the street but I didn't realize he was mine until he got a little closer.
ーI saw a cute dog walking towards me and then I realized it was my dog.
「可愛い犬が私に向かって歩いてくるなと思ったら、うちの犬だった。」
walking towards me で「私の方に歩いてくる」
realize で「気づく・理解する」
ーI saw a really cute dog walking down the street but I didn't realize he was mine until he got a little closer.
「すごく可愛い犬が道を歩いてくるのを見たんだけど、近くに来るまでうちの犬だとは気がつかなかった。」
walking down the street で「道を歩いてくる」
get a little closer で「少し近づく」
ご参考まで！
カナダ 
