Personally I don't like this because to me it violates a fundamental principle of Democracy and removes power from the people.
The negative side of this is when Representatives are doing a great job, why risk jumping ship to a less known quantity? If my Rep is someone like AOC, then by golly I'd want her for life if she maintained my support.
The real root of the problem resides in campaign finance & election reform, where newcomers are at a disadvantaged state facing an incumbent. This can almost mathematically be offset if this aspect of the system is corrected.
As far as age limits go, here in America we already have age-minimums. Can't be a House Rep until 25; Senator until 30; President until 35. Clearly there is no representation for anyone below 25 whatsoever and their future in this world. That also skirts the real problems with the literal meaning of aging: cognitive and physical decline. While people may not need to be at peak performance, there are so many more probabilistic risks with those past retirement age / pensioners that it becomes a liability. Not only that, they're less invested in the future because they're frankly not long for this world. That said, given my belief here contradicts my take on giving power to the people, I'd say lift all age constraints and again fix the campaign finance / election reform system so the electorate is actually more responsive to political stagnation.
Voters should also be able to (a) Recall any Congressperson, House and senate, and (b) There should be federal-level referendum measures to enable direct / participatory voting by the people -- even if the threshold is at a higher bar, like 65% or 70%.