If you really want to do it then don't give up! I'm 40 something.... am a mum, work full-time in an industry not related to education but have taken days off here and there over the past year to observe in a variety of secondary schools. I also arranged with one school to come in and observe the first lesson one day a week for an extended time period and arranged with work to come in late one day a week and make up the time at the end of the day (therefore not using more holiday to do this). I also needed to do an equivalency test to get my maths where it needed to be. I have been offered a GTP place so, I'm living proof it can be done! Both my supporting school and the Uni were impressed with the variety of schools I have been into and the observations I made while I was there. I keep a notebook and after each observation rush off and write about what I've seen so I don't forget - all this info found it's way onto my applications and gave me plenty to talk about at interview. Good luck!