... while still at school (i.e. aged ~15). Algol 60 was clearly elegant and 'well-designed'. We learned it in an after-school club run my one of the maths teachers (thanks "Jake"). It was followed by Fortran IV for the comparison with a language that while very useful was about as horrible to use as a language could be. We wrote on coding sheets which the teacher posted to a nearby university, and we received the corresponding punched card deck and lineprinter output showing our syntax errors "in as little as a week".
NB: I freely acknowledge that there are worse-looking languages than Fortran these days: Perl, APL, Mumps, IBM mainframe JCL for starters
Our first teaching language at university was BASIC, which I'm not ashamed about
To paraphrase a well-worn metaphor: C
PS: non type-safe languages
Languages in which white-space is significant