Like C-H, I would tend to agree with Lyledunn.
Please also bear in mind that HV training is an on-going thing, as in once you have a certain qualification in HV work, the need to keep your knowledge of new techniques and safety requirements is a constant thing.
Don't get me wrong, there are a few people here at ECN that are experienced in HV and EHV work and really enjoy it and I am most certainly not trying to put you off getting into this sort of work, I prefer it to house re-wires and so forth.
Only competent persons work on MV/HV/EHV systems, this sort of work is never bodged, so you don't usually have unusual wiring practices and so forth.
I'd say get into it!!.
Let's face it, these days if you're not young, you're old - Red Green