I am just entering my aspirancy year (first of five years of formation). I am currently 42 with 6 children (2 late teens and 4 under 8) and a 7th on the way in January. I had been considering it for the last 4 years, but always figured I was too young. It seems my diocese disagred.
My diocese and many others have noticed a definite graying of permanent deacons and are seeking to reverse the trend. Something like a third of the deacons in my diocese will be at or above the retirement age of 70 by the time my class completes formation. Given that we only average 1.2 deacons per parish this is very worrying. It is too the point that we were told that if two men were of equal qualifications with one 40 and the other 55 they would take the younger man every time. The inquiry sessions specifically asked for younger men.
There were questions about the time required for formation when raising a family and working to support my family. As I discussed with the selection committee, one of the thoughts even before the second vatican council was that deacons were to be actively engaged in their communities. As one priest said, deacons can bring the Gospel to places that a priest cannot. His point is that a deacon is not just engaged in the parish and liturgical functions, but rather brings the light of Christ to those outside the Church community.
This thought of ordaining working men that are still raising a family is not that unusual outside the US. The US is an oddity in that regard. That is why you see more and more diocese rejecting the idea that men must be done with one phase of life before being ordained. If the Church only intended men that could dedicate 20+ hours a week then the minimum age of 35 would not have been set at an age many men still have young children. As I understand it the fathers of Vatican II specifically lowered the age form an original proposal or 40 or 45.
Now just having started I cannot say how difficult it will be, but if you feel called then talk to the head of formation. They may tell you that you should wait until any children are minimally teenagers, but you may find that they are glad to have young men. To give you an idea, our last class (we only do one class every 4 years) has 9 men in formation. Once they encouraged younger men my class will start with 21 men and they had to turn away men because of too many applicants.