It's important to realize that being a furry isn't necessarily a "lifestyle", it's more a hobby. Don't think of being furry as similar to a sexuality because it isn't , there's no reason to tell your parents you're a furry unless you find a reason, so no need to worry about it yet. Fursuits are expensive! (A cheap one can cost $1,000! And that's generally cheap!) So it will take a while for you to get a fursuit. You can still go to conventions, just tell your parents it's an anime convention or something. Really, there's no reason to tell anyone unless you find a reason, for example you have enough money to buy a fursuit and you really want one, then telling your parents is a good idea. But to go about telling your parents, keep it casual, don't treat it like a perverted fetish (like coming about it all nervous and scared) or they'll think of it as a perverted fetish, just treat it as a nice little hobby you like to do, like "Friends and I really like this anthropomorphic art of animals and such, we go to conventions and stuff to discuss it, it's really cool! We also cosplay the art like people do in Star trek and anime conventions to show off and have a great time!" Something like that.
For being gay, well, that's up to you. I found sexuality is slightly different, coming out about it can be really liberating and make you feel quite better. I'd wait until you're a bit older unless your parents are very open about homosexuality, in which case go for it. But if they're not, it's a good idea to wait until you're, say 16 to 18, in case anything BAD happens, not that it will necessarily (it's quite unlikely it will). But yes, I would say coming out to your parents about being gay EVENTUALLY is a good idea, because it makes you feel quite a lot better, happier and freer, it's hard to explain but you don't feel self conscious about being gay. EVEN if your parents have a bad reaction you still feel like you're open with yourself. I don't consider furryism as significant as sexuality so I don't have a need to tell everyone I meet I'm a furry, I just tell people when they ask xD
EDIT: Also HAH! that was the Avi I used when I originally joined the fandom too
Ah memories~