Hi, first time posting here, long time lurker, just looking for some advice hopefully.
I work as a receptionist/office admin for a small plumbing company, like 11 people in total small. I started here back in March and in general it's been grand. Pays over minimum wage and I can work slight flexi hours (the bar is in hell I know). I started on £10.50 and within a week or two was told I would be getting £11 an hour from now on. A month after I started, another person started in the same role as me. We do the same job for the same amount of hours, 40 per week.
Here's where I need advice. We have a shared inbox that all company emails come to and we all reply from. When I was searching for an email earlier I stumbled upon an email from my boss to our accountant saying that from July 20th my colleague is moving up to £12.50 an hour. I'm not mad at that obviously, they should get paid that or more but they don't do anything extra or more than me in our role. I'm not sure how to it up to my boss that we should get the same wage for doing the same job. I started a month before her but I should mention I'm 22 and they (the other admin) are in their 40s so I'm thinking it could potentially be an age thing I'm not sure. It's also that I found out by reading an email that I was likely wasn't meant to read so little bit worried he'll question on how I found out and think I was snooping.
I'm in the UK, NI specifically just for reference.
Any advice would greatly be appreciated. This is only my second job in life so I'm still a bit skittish about bringing up issues in case it changes the dynamics and I end up in a worse position from it. Thanks in advance <3