Can I file my tax return as jointly when my wife doesn't have itin/ssn?

Last year we filed jointly and that my wife was applying for ITIN (that's what the accountant we used told us to do). But when we finally managed to get our tax return sent it he said it was too late to apply for the ITIN (wouldn't be processed in time for the ITIN to attach to the tax return or something like that) so to just skip that and do it this year instead. However, life has come between and now we're in the same position again with not enough time to apply for ITIN. Can I still file jointly, or should I just file by myself? She doesn't have an income. Will it affect the tax return in any way? What's the best way to go about this?