It is not uncommon for the "Ready for decision" stage to last for more than a month. So there's nothing to actually worry about. I think your submission is making progress at a decent pace. However, since it's been 5 months since initial submission, and nearly a month since the last status change, there's no harm in sending an inquiry to the journal now. Since this is your first submission, you should be mindful of the tone and level of politeness in your email. We have a handbook that provides templates for communicating with the journal. You can take a look if you wish to.
- Is it a bad sign if the status shows "Ready for Decision" for a long time?
- How long does the status "Ready for decision" take?