Similar story really, started playing bass mid-teens (no grades, no other instruments other than recorder in Primary School), in & out of bands to my mid-20's, then life got in the way. Played a bit of guitar, but nothing serious.
Stopped playing for a few years, then started doing a part time recording course at the local college, started playing guitar a bit more as well as bass for song writing, and that kind of took over. Played bass on the recordings, but nothing more. That project developed into a band, but then that band folded, and basically stopped playing for a while and kind of fell out of love with playing.
Fast forward a few more years, looking for something to do, saw an ad for a bass player in a new originals band, answered the ad, met with the others and got on with them. A few line up changes and about 8 years later, we've recently released our first album.
The beauty of doing the recording course, playing guitar & songwriting, I think I've picked up an appreciation of "serving the song".