Credit question

Ok so I know 0 about credit. However I’ve gotten a credit card. Technically I have 2 now for reasons I’ll explain in a Sec. when I went to the bank to get my debit card I got a student credit card at the same time to help start slowly building credit. So far I’ve spent $20 and literally paid it off like a week later.

Then my dog got sick and I took him to the vet. I had to take out a credit card to pay it off. I’ve already paid off $150 of almost $700 that the bill came to. And I’m going to pay another $150 once I get my check for the last two weeks of work, which should be around $600 from the hours I worked. My plan is for every paycheck I pay $150. Which would be $300 a month. And for my last payment I’ll probably do 150 plus the rest of the bill just to get it out of the way. If I pay it all within 6 months I don’t have any interest how much credit do you think that would build?