I don't wear but I'm in a similar situation, so I'll give you my $0.02.
Alright I am 20 year old male N3. My hairline is too high for my age at the temples. I want to get a partial piece to put in front. Of course I have a few questions.
1)Is it even possible? I mean Im sure people do it, but does it look natural and is it undetectable?
In theory yes. It may take a bit of effort and trial-and-error, but you'll certainly be able to create an undetectable look. I'm not yet sold on partials, so it may be that getting a topper is easier. But, yes, one way or another you'll be able to get it to look undetectable. With hair systems the problem is not that they in themselves look fake (although if done badly, of course, they do).
2) About how much would it cost?
I think most pieces are around $200, and last about 2-3 months. Add in some additional cost for supplies, possibly cut-ins etc. This is if you go mail order, with salons it's a LOT more expensive.
3) How often would I need to get it replaced?
If you're doing it yourself, some do daily or every other day, but you can get away doing it once a week.
If you go to a salon they might try and get you to keep it in for up to a month.
4) Would people be able to tell because of the change of going from receding temples to full head of hair?
It depends how extreme it is. If you're going from a sharp level of recession to a 16-year-old hairline, some people may notice the change. There are ways to work around this, though.
5)Would it be detectable upon touch?
It depends what you mean by touch. The hair itself will feel fairly normal, but the scalp might not. Generally if someone's properly running their hand through your head there's a good chance they'll realize.