An Iguana Lizard [From your photo, even though it's technically a lizard.  You don't call a tiger a cat even though it is a feline.]

I love my aunt's garden. It is a carpet of sweet-smelling herbs and flowers. and it has There are many fruitful trees as well. I Sometimes, I go there to pick some flowers and spend a lovely time with my aunt. However, today while as we were sitting in the garden, I suddenly saw an iguana  lizard watching staring at us with its bright eyes. I leapt to my feet and ran inside the house keeping leaving my aunt out there alone. She just laughed because she is used of course to seeing insects all these critters in such a big grden. Concerning As for me, I'm still imagining its ugly face. It is ugly and horrible. I hate it.

You should be ashamed of yourself leaving your poor aunt alone to fend for herself. What happens if something was to befall on her? :)  Iguanas are beneficial creatures.  They eat bugs.  Would you like to have an iguana or some giant bug staring at you? LOL :)

A Lizard

I love my aunt's garden. It is a carpet of sweet-smelling herbs and flowers, and it has many fruitful trees. I sometimes go there to pick some flowers and spend a lovely time with my aunt. However, today, while we were sitting in the garden, I suddenly saw a lizard watching us with its bright eyes. I leapt to my feet and run ran inside the house, keeping leaving my aunt alone. She just laughed because she is, of course, used of course to seeing insects in such a big garden. Concerning me, I'm still imagining its ugly face. It is ugly and horrible. I hate it.

point to be remember, it is correct to write, "sometimes i go" but not write, "I sometimes go". 2nd it is better to write a story in past tense 

A Lizard

I love my aunt's garden. It is a carpet of sweet-smelling herbs and flowers and it also has many fruit trees. I sometimes go there to pick flowers, and spend a  time with my aunt. However, today while we were sitting in the garden, I suddenly saw a lizard which was staring  at us with its bright eyes. I leapt to my feet and leaving my aunt alone, I ran into the house. She laughed at it because she was used to seeing insects in such a big grden. however I still remember lizad,s ugly face. It was ugly and horrible. I hate it.