Since you are so early in your career, in my opinion you are much better off leaving the paper where it is and hopefully it will be published soon. It's possible that you could have initially aimed higher, but because the refereeing process can sometimes take 6 months or even a year, you definitely don't want to withdraw it now- it could delay acceptance and publication by a long time. Even if you get a favourable referee's report, there's no guarantee that resubmitting it to a better journal will result in a favourable report.

At your stage, it's better to get papers accepted and published, even if they're at lower-rank journals, than to be waiting over a year for a decision by a better journal.