Assalamu alaikum ustadh. I wanted to buy someone Mushaf another person pushed me and payed. I'm so upset that she did that, I feel it's selfish to steal others rewards, I feel unchosen by Allah cause things like this keep happening where someone else earns more reward than I do, any advice

Ustadh AbdulAziz al-Haqqan

‎You are rewarded for your intention, as the Prophet ﷺ‎ said that whoever intends a good deed and does not do it, Allah writes it for him as a complete good deed. She did not take your reward, she raced you to a good deed, so race her next time.