Hmm, in my past experience studying overseas. There is some classmates who are substantially older than the average age of the whole class.
Spoke to one of them and he told me he previously is tradesman (tukang electric/builder) who is keen to improve themselves. They do have money collected in prior jobs hence they can sustain themselves and focus in the studies.
Just a note these tukang are actually quite well off compared to equivalent in Malaysia. Just see how much they charge for workmanship for simple task and you get the idea.
As long you have finance backing in some form then why not
28 years old too late to graduate?