I never read SF until my late teens, (except HG Wells - Invisible Man) though there were wireless serials-
Journey into Space (we talked about it at school the next day)
Day of the Triffids (Wyndham)

At college more fantasy than SF - was introduced to Tolkien & White

After college shared a hostel room with a discerning SF fan so found all the authors writing in the 60s with ideas that were (then) before their time - and now have happened. Social problems like an aging society.
Some of the short stories are gems.

Asimov's reprints are interesting - he doesn't spoil the story with an introduction, but writes an 'afterword' to tell readers about how he came to write that story, and where the science behind it has been disproved.

Zenna Henderson's People series - mentioned above - I got 1 out of the library years ago, haven't seen any more of them.