I would say probably closer to 4 1/2. Definitely a mountable buck and if it's only $400, go for it. It is going to cost me $460 for mine this year and my brother is getting his son's buck mounted and it's going to run him over $600!

no younger than 4

3.5 yrs To each there on whether or not to mount. Depends on how many you want? I'm going to guess you will kill a couple bigger in your lifetime so if it were me I would most likely hold off.