When you grow up with a writing system you think it has always been like that. And the Latin script has been the same for a very long time, but there have been some additions over the centuries. One that is very noticable if you read old Latin texts is the lack of the letter J.
I was used for both the “i” sound and the “j” sound. Over time people started putting a little down stroke on the i to show that the consonant version of i was meant, and it eventually became its own letter. Find the story about the other additions to the Latin script in the video on this post.