The Lord leads. Pray about it is the first thing I'd think of doing.
But, yeah.
There can be factors why not? LIke they are not a christian, they are best friends with you for some reason that says you could never make it work. Idk the reason(s), there just are
But, yeah, why not date a best friend, a subject of prayer, like everything else, but, if you have everything in common that would forward you both into a Loving relationship of Him, then why not?
Especially if God is making it happen, don't deny God's leading or become a Jonah story.
And, so, if you do things together and if you like doing things together, and, have for like, FOREVER, you would just be acquiescing (I love that word, but have no idea what it means really), syncopating (I love that word but I have not idea if it really makes sense here) that relationship into a consecrated, holy, matrimony of forevereverafter
I think that we must go on faith in life and accept God's prompting and realize this 'grace' and IF your best friend was becoming stronger and stronger in Christ and you were advancing too in maturity in that spiritual way I would say to definitely RISK it not working out because BOTH of you are believers, and, would understand that a BREAK UP would not be intended, likely, to make it so you could not still be friends, and, I see why not still, best friends.
Good Q, Mammy.