It is a personal decision, one an individual must take time to think about for themselves. I know in some denominations it would be considered highly immodest for a woman to wear a bikini, but my personal opinion is that people should wear whatever they feel comfortable in.
Do you think it is okay for a Christian woman to wear a bikini that doesn't show "too" much?
If it could become a stumbling block for your brothers in Christ then I would be careful how much skin your show. Its really hard for men, especially young guys because when we see too much skin, sometimes we can get wrong thoughts which can lead to lust in the heart..which is sin.
Like if a woman walked into church with her cleavage exposed...thats gonna grab attention in a negative way.
Beauty isnt showed off, its hidden away in love.
OR you could just ask a pastor since hes actually educated in the word of God. Ask important questions to spiritual leaders appointed by God.