Well, BASIC was --- but the CTSS timesharing system had already been in use at MIT since the summer of 1963: http://www.multicians.org/thvv/7094.html
There are other earlier systems: JOSS, which featured a rather BASIC-like language, was in service by January, 1964: http://en.wikipedia.org/wiki/JOSS
And both JOSS and CTSS had been demoed in earlier form before going into general service --- in fact, the first primitive CTSS demo was in 1961.
Well, BASIC was --- but the CTSS timesharing system had already been in use at MIT since the summer of 1963: http://www.multicians.org/thvv/7094.html
There are other earlier systems: JOSS, which featured a rather BASIC-like language, was in service by January, 1964: http://en.wikipedia.org/wiki/JOSS
And both JOSS and CTSS had been demoed in earlier form before going into general service --- in fact, the first primitive CTSS demo was in 1961.