I was doing a part-time Masters degree when I suddenly started to feel broody, aged 32. I wanted to start trying straight away, but my other half said he didn't think it was a good idea to study and maybe go through pregnancy at the same time. Humpf. I disagreed.
However, how right he was!!! You're doing the right thing and concentrate on one thing at a time. You need to give your studies your full attention as once you've got the qualification you have it for life. When you're TTC and going through the first trimester feeling sick, faint, exhausted etc, you won't feel like doing anything else.
I remember feeling these things and thinking "thank God I didn't go through this while I was writing my disseration!".
Good decision! Keep up the hard work and good luck!