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Lucky Chance
Spring is coming..There weren't anything events at the Silver Shoe Farm.Tilly's riding skills are improwing by the day,and she can't wait to go to Pony Club Camp,but first there's an exciting new arrival to welcome to \Silver Shoe Farm-new foal will born soon!
This foal had name Lucky Chance,because his mother was old horse,and hadn't many chances togave birth.Tilly went to camp and she was the best horse rider.She returned home very happy,and Lucky Chance bored for her.
It was fantastic spring.

Spring was coming..There weren't any events at the Silver Shoe Farm. Tilly's riding skills were improving by the day, and she couldn't wait to go to Pony Club Camp, but first there was an exciting new arrival to welcome to Silver Shoe Farm - a new foal would soon be born !

This foal will be named Lucky Chance, because his mother is an old horse, and hadn't much chance of giving birth.

Tilly went to camp and she was the best horse rider. She returned home very happy, and Lucky Chance had been born for her.

It was a fantastic spring.*

The tense in which this is written will depend on whether you are telling the story as taking place now, in the present, or you are recounting it from the past.  You started in the present, but then went in to the past tense.  However, you should maintain consistency, so I have corrected it as an account of something that happened in the past.

* You could say 'It has been a fantastic spring', or 'It had been a fantastic spring', depending on when the story is being told:  in the first case, immediately afterwards, and spring is only just finished, and in the second case, quite a long time later, and you are looking back.  'It was a fantastic spring' will do for either case.