Hi icelollycraving!
Its great that you have decided to lose the weight and improve your health.
Unless you really want to go to ww or sw I'd recommend myfitnesspal.com as its free (although see that some people need the meeting for extra motivation).
I used myfitnesspal in conjunction with low GI and then lower carb diet last year and lost around 4 stone to get to target. It does take a while though (esp if you even more to lose) so you need to see it as a lifestyle change (which from your OP you are).
re: exercise can't get better than 30 day shred (and when weather improves couch to 5k) - worth investing in dumbells, ideally 2kg - they will be heavy to start with but weight training is important to prevent you from losing muscle mass as you lose weight.
I also really recommend hypnosis, really helps when the willpower starts to flag. Some like Paul Mckenna, but have a look at Lisa Jackson's adore yourself slim.
re: diet - calorie counting is ok, but I think you get better results health-wise if you go low GI and cut the white stuff (white flour and sugar etc) from your diet. Its highly addictive and not especially nutritious. I rarely eat grains at all now (even in maintenance) - means I'm less likely to crave sweet stuff - and I am very fit and active.
re: telling people - I only told people when they needed to know, eg if invited to someone's house for lunch!
Good luck!