I'm 38 and bought my first bass about 6 weeks ago. I have never played any instrument or taken a music class. I've been a fan of music (obsessed with it actually) since I was a kid. I've sang for years. Run the sound board for my brother (who at one time was considered one of the top banjo players in the country) and even engineered and installed car stereos and home theaters.
Each time I tried to pick up an instrument and learn to play, I got discouraged very quickly because I didn't see enough progress. My brother tried to teach me, but he has no music training. He's self taught. Basically someone who was "born with it". He doesn't know how he plays, he just does. I tried to play piano once, and after about a week of trying, ended up quitting.
My entire life, I've loved the sound of the bass. I have spent countless dollars on subwoofers for my car and home just to hear that sweet bottom end.
I decided to try to play the bass. I bought the gear, and made the commitment that no matter how frustrated or impatient I get, that I will push through it. I want to PLAY. I want to play so bad I can't stand it. But at 38 I am a lot more mature than in the past. There is no short cut. I figure that it will be a lifelong quest for learning, not only playing bass but also music.
A funny thing has happened. I actually enjoy practicing. I find ways to challenge myself and judge my progress other than being able to play actual songs. I'm not there yet. I can noodle around and play a few songs, but not like I want to play them, not using the bass line in my head.
On this past Thursday, I started practicing permutation exercises. To play cleanly with no errors, I had to slow to 55 beats per minute. AGONIZINGLY slow, but it gave me time to get my fingers in position to fret the note. Today, three days later, I've more than doubled how fast I can play the exercises cleanly. Tonight I was playing at 150 beats per minute CLEAN. No errors. I felt really proud of myself.
I do my best to practice every day. Even if it's for just a few minutes. Sometimes I go down before I go to bed with the intent of practicing for 15 minutes, only to look up and notice I've been there for 2 hours or longer. I can't walk by my bass without a strong urge to pick it up. It sits outside my bathroom, and when the water is warming before I take a shower, I'm playing, even for that few seconds.
The key for me is having realistic expectations. I have a good teacher. I have seemingly unlimited amounts of desire and motivation. I work on exercises, ear training, reading, and when I need a "study break" I put on some familiar tunes and try to pick out the notes. It's a thrill when I can play the song about 75% (I always seem to get lost on bridges and such).
The next thing I want to do is find someone to play with. Once I feel like I have enough skill to do so, I'm going to try to find others to jam with. Maybe visit local music stores and see if they have a bulletin board so I can try to get a "jam night" set up somewhere. I sing in church, and am blessed to know lots of great musicians. I will try to hook up with them as well. I just have to accept that it's going to take YEARS to get to the point where I can be considered "good". I'm fine with that. I just want to play.
Never, never give up. You're not too old. Stay positive, set realistic goals, and practice even if it's for a few minutes. You don't need hours a day to get better. Five minutes is better than zero minutes.