It's actually a paragraph, as there are 3 sentences. But yes, the grammar seems fine to me. The only error was that you need 'a' before 'speaking exam', and it would be more natural to say 'an oral exam'

It was during a short journey with my family that I paid a visit to a farm. It was a sunny day. When we arrived there, a sea of flowers made my eyes brighten up and lifted my spirits. - This is fine, however I think it could be better if you said "It was during a short journey with my family that I paid a visit to a farm, on a sunny day... " The reason being is that it's a bite repetitive to have two sentences starting with 'It was', otherwise it's nicely said and you've used some interesting expressions. :)