My situation was the exact same as yours - with only very slightly different ages. I started really when I was 8, did Grade 7 at 15. I had a horrendously nerve-wracking time in the G7 exam itself (though I passed fine), but that together with pressure of school exams gave me reason to stop. I couldn't really find the time nor a piano nor the money for lessons when at uni.
So ten years later (same as you) without having so much as touched a piano during that time, I took it up again at 25 and got my Grade 8 a year later. Have to confess the Grade 8 was pure luck (big time nerves and a cold let me down BAD) - I believe the examiner was just too nice to want to fail me

. I am now aiming towards a diploma, slowly, while working on playing finesse and all the details beyond the notes which is needed for that level.
Anyway, what I mean to say is it is definitely very very possible (I am not musical genius in the least and I managed it). The thing is this time, since you are an adult with no parents to push you (actually it is better this way) the motivation has to come from you yourself. If you love it, you will be putting in the effort into finding the time (i.e. giving up some TV etc) and patience to practice without too much trouble. As an adult, I think it is also easier to try and grasp what your teacher wants you to do and try to apply it to the playing. I am thinking about music in a way I never did as a kid. You can also have a say in what pieces you would like to play, listen to what you like and generally have more say in your learning.
Another thing is I am very very lucky that I found an amazing teacher (I can't say enough about him) who I believe is the reason why I managed to get the Grade 8 (with some help from that nice examiner). I really lucked out with getting a teacher like him. I am not too sure how one would really go about searching for one, but I'd say if you are serious about it, try asking round those in the know who a good teacher might be, one who can take you through Grade 8 and beyond and one whom you feel you can get on with and establish a good working relationship.
Good luck and most of all, enjoy it! Realising you want to take it up again is a huge step in the right direction. Everyday I curse myself for not keeping it up at 15 and also thanking my mum for making me stick at it from ages 8-15 because there was a time I hated the piano so much I preferred to do homework or eat vegetables!