help to buy equity scheme

[CAH706]

I'm thinking of buying a new house and was looking into this but have a couple of questions....any help appreciate.

Firstly, I don't think I'd get a mortgage for 25 years (im 44)which seems a requirement. Does this rule me out straight away?

Secondly, I have more than a 5% deposit available. If I did qualify for the scheme, is there anything stopping me paying off some of the mortgage part straight away .... subject to usual mortgage fees?

Thanks