I started singing at 34, am now taking lessons and am delighted to find out that the female voice reaches its peak in the mid-forties - so middle-aged women are certainly not past it! Since starting out I've gone from adequate to good - occasionally very good. There's still plenty of potential for growth.
I play guitar in a very basic way (improving only slowly) in order to accompany my singing. I used to play guitar as a kid & so had a tiny head-start when I picked it up again a couple of years ago.
I started by singing at gettogethers in festival campsites, at singarounds, folk clubs, and folkie gatherings. It took longer to feel comfortable singing & playing in front of friends and family. Though my husband's family surprised me in the support they gave - I was shocked to find they actually wanted to hear me!!
Supported in my choices? Well - friends that I play & sing with are always encouraging, and people in pubs compliment me (blimey!!). My husband, Mark, has always been my strongest critic and is disconcertingly honest about my flaws - but that has paid off (along with lessons) and he is now 90% complimentary. That is clearly support that I've earned, rather than a default partisan support.
My other big support is my daughter, Amoret, who has played and sung with me and is now branching out to sing and play solo (finally taking Bill Sables' advice :))
Support is very important, especially when you are starting out and don't have an accumulation of self-confidence yet! Fortunately folkies are a very supporting breed - its like a huge pool of instant friends.
Music shapes my life in terms of singing being the thing I love to do, and improving that is an interesting journey. It shapes my life in terms of the sessions and festivals that we go to as a family, and the passing on of the passion to my daughter. It shapes my life in terms of the friends that we make through music. It shapes my life in terms of self-respect : I may be a fat old hippy woman - but I can sing. So, music is vastly important to me now, and all this has emerged over the course of 4 years or so.
So my advice to a middle-aged woman starting out in music is to really go for it, enjoy it, be generous with your music, don't let anyone put you off - but do listen to valid criticism, - and don't forget that its only you that knows you haven't been doing it for years. One of my biggest hurdles was that I felt that everyone else was somehow a more "proper" musician - on closer aquaintance it turns out that an aweful lot of people feel this way. I've also learnt that making a mistake or mangling a song is not the end of the world. Make light of your mistakes and everyone else will do the same - and never over-apologise.