YOU SAID:

i rode the pony and it was very beautiful

INTO JAPANESE

私はポニーに乗りましたが、とても美しかったです

BACK INTO ENGLISH

I rode a pony and it was so beautiful

INTO JAPANESE

ポニーに乗って、とても美しかった

BACK INTO ENGLISH

Riding a pony, it was so beautiful

INTO JAPANESE

ポニーに乗って、とても綺麗でした

BACK INTO ENGLISH

Riding a pony, it was so beautiful