I like Captain Marvel, and if those are your only 5 stars, then ranking her some will give you a hard hitting champ that will help you for a while. Maybe as high as rank 3, but not more than that. In a few months you'll have a few more 5-stars, and likely one that will be more worthy of ranking.
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My first 5* x 4/55 was captain marvel and I don’t regret it. I still use her now heavily on my regular questing team.
We can’t always wait on the perfect champ my friend. Sometimes we use the champs we got to help us advance for a time.