Can I perform Istikhara as Christian yet to revert to islam

Assalamalaikum. Am a Christian and from a very strict and religious Christian family, I love this guy and he began to teach me things about Islam and I fell in love with Islam. We both would want to get married but my family and his are not in support of it. I want to revert to Islam, but don't want it to be because I love him. I also don't want to hurt my family mostly my mom. We've done things that are wrong in Islam and decided to stop. He loves another Muslim sister and it scares me a lot I feel am loosing him already. He said he would like to perform Istikhara so as to do the will of Allah. Now my question is can I also perform Istikhara despite I not being reverted to Islam yet. If yes how should I go about it. Wa-Salam