This will depend entirely on the individual child and your observations of their abilities. In some cases, a 6 year old has no problem building a set designated for 7 to 14 year olds, although it may take them a little longer. However, some parents on Amazon have reported that even their 8 year old has trouble deciphering the directions, so you’ll want to take this into account when making a decision. To make sure your child enjoys building their Technic set and to avoid frustration, it may be best to stick to the age guidelines recommended by LEGO. A set that contains hundreds of small parts could quickly overwhelm a younger builder, especially if it’s their first encounter with the Technic line.