I am sure you have seen newspaper columns and TV programmes where people casually talk about stuff like adjectives and adverbs - and they are absolutely clueless. People grow up reading and watching those, and start doing it themselves. Vicious cycle.
Well, I am here to make you feel better. Much better. Just don't listen to those clueless people. Consider the following:
all the ten fine old stone houses
Poutsma, Kruisinga and Zandvoort say that only 'fine' and 'old' are adjectives. Jespersen says 'the', 'fine' and 'old' are adjectives. Sweet, Curme, and Onions say that all the words preceding 'houses' are adjectives.
They are - OK, were - all prominent grammarians, whose views are often lumped together under the label 'traditional grammar' - which is unfortunate, because they don't even agree on what adjectives are. My point is, why should we.
Wait, it gets better: grammarians don't even agree on what they should categorise words into. Some grammars recognise eight parts of speech; some nine; some six; some four; some three. So you see, there is no point in being dogmatic about what to call what.
Given all that, it is almost funny the way some people feel strongly about what they think is their own view; when it is even slightly attacked, emotional reactions can follow. Gosh, some people have a lot of growing up left to do.
You know, there are no adjectives to talk about in the whole universe - unless we agree on what they are. To reach that agreement, we discuss - which is the whole point (as well as joy, by the way) of grammar.
Grammars worth reading do just that: they tell you why they recognise such and such categories, how these categories function, and so on. In this sense, grammar is like philosophy: it is a dynamic intellectual process to get involved in, rather than a set of terminologies to accept (or reject).
So, whenever there is a question about what is the 'right' part of speech a given word belongs to, take it easy. We can discuss it, but there is no need to worry about it. If you are not sure, hey, maybe not even professional grammarians are. There is no need to bluff.