A musical education for a child is much easier than for an adult. A child is still not loaded with big life problems, so he has the time to master an instrument such as violin.
Also just like any other education, foundations of music education are easier to learn at an early age. As for the adults, usually playing an instrument is mostly a hobby.
And as in any hobby it is always useful to think if you really need it, before heading off to the store. At that point if you really want to play a violin you’ll find the needed time, most people can do it.
Even if you are completely busy, for example with work and caring for a small child, there will be a solution. A good one is to start learning simultaneously with your kid, it will give you a mutual interest and make the learning process more fun.
Yet the main problem for you most probably would be time. Mastering a violin will require a lot of time. Only hours and hours of practice will make you a good musician, so if you initially want to make these violin lessons useful, make sure that you have enough time for them.
There are lots of people who give up violin lessons, only because they think that they are just not capable to play this instrument. But this is wrong and only patience will help you not to join the ranks of the “lost” violinists.
So make sure that you have enough patience. As for some real numbers you’ll need around 30 minutes of practice every day for beginner level. Such time span is not difficult to set aside during a day.
Another important thing is defining the style that you want to play. If a saxophone for example is mostly used in jazz music and banjo in country or bluegrass, violin can be used anywhere. This instrument can be used to play anything, from gentle classic accompaniments to fast Irish dance jigs.
The style of the violin and the time required for mastering this style and practising will be different for each style music and you will also need different teachers. So before you start learning for example the gypsy violin, make sure that this is exactly the type of violin that you like and that you want to master.
Remember that learning will be more difficult for an adult. As a child you usually don’t care much about how you play and how fast you learn. You just play, because mostly you are told that you need to learn to play the violin.
As an adult you will constantly be paying too much attention to how good you play and some other things. This often results into dropping the violin lessons, because “it is just not for me”.
But don’t let this affect you, there are thousands of people who successfully mastered musical instruments during their mid age. If you are really passionate about the instrument nothing will be able to stop you.