The only time I was ostracised as an older learner was when, as part of the university curse I mentioned above I went to Italy to do three weeks fieldwork.
The look of shock on the young Italian students faces when I arrived was amusing, the way they completely ostracised me while I was there was not. Mature students were obviously not a feature of Italian universities and they felt awkward with me, so avoided me.
After a week of my own company, plus realising the fieldwork I was involved in was poor quality, poorly organised and at times dangerous, and here my age and self confidence came to the fore, I rang my tutor, told him how poor the experience I was getting was and told him I was returning home the following day, to join a field work project I knew of quite close to my home, where I had worked before.