1. You could wait until next year. You can still contribute for this year
before April 15 of next year.
2. You could contribute and then if you're over the limit, withdraw it
before April 15 and it will count as if you didn't contribute in the first
place.
3. You could contribute and then if you're over the limit, recharacterize it
into a Traditional IRA contribution. And then you can convert it to a Roth
IRA again.
4. You could do a Backdoor Roth IRA now -- make a Traditional IRA
contribution and immediately convert to a Roth IRA.
(Note: for #3 and #4, for the conversion part, make sure you don't have any
existing money in Traditional IRAs.)
#4 is the best. Backdoor Roth IRA is used to contribute to Roth IRA when
your income is over the limit. But there is nothing to lose from doing it
even if you are not over the limit.
#3 is worse than #4, because the earnings between contribution and
conversion are taxable on conversion.