I'm new Here and I need some help.

I'm 15 and I just recently got a gym membership close to where I live. I'll be honest with you, I've been overweight all my life. September 2007, I weighed a whopping 175 pounds at the age of 14, I've reduced that to 150 Pounds and I am 15 now. I still am fat (thing is, it may just be me, but I feel fat and I want to lose it, people around tell me that I look fine and that I am at a right weight and size for my age, but I'm 15, around 5"6 and 150 pounds...) Edit: I'm also happy that I am not overweight anymore!

I've only been to the gym three times and I everytime I go out of the gym I feel a major difference. I would warm-up on the bike for about 3 minutes then hit the treadmill. I'd do some moderate HIIT... I'd do a slow walk (4KM/H) for about 3 minutes then do a pretty fast-paced jog (18KM/H) for a minute then go back to my 4KM/H walk for 2 minutes and I'd repeat that. I'd do HIIT for 20 minutes and then hit the weights. I'm a total "newbie" when it comes to Gym terminology, do don't expect me to get everything right. But I'd do a decent workout, mainly working out my triceps, bicep, shoulders & back. I'd do 4 sets of 10-15 reps. My arms feel better and I can already see the muscle kicking in on my biceps after just going to the gym 3 times. I plan to get a normal routine and go to the gym 5 times a week whereas the weekends will be my resting periods.

Now, I've basically explained to you what I do, but I need you to help me. Could anyone possible suggest a nice workout routine that I could follow and that isn't TOO strenous, but I want some results pretty fast and I'm willing to work for them.
Also, I need a diet that I can stick to. To be honest with you, the only reason I lost weight was because I wasn't eating much at all. I'd have a bowl of cereal for breakfast, skip lunch and have perhaps a plate of rice or pasta for dinner. I'd drink tons of water as well.

Meh, well, that's me. (Also, one odd fact: My family doctor said that I would never be able to get a really "lean" look because of my Broad shoulders apparently.) But... yeah.

Thanks in advance.

Accidently quoted instead of Edit.

well you could go with an upper/lower split, or a 3 day split. which ever fits you. i would suggest a 3 day split though.

try something like this
day 1 Back/bi
Deadlift 3 sets 8,8,6
dumbell or barbell curl 10,8,6
lat pulldown10,8,8 or pullups (try to get 15-25 per pullup session depending on your lat strength, set range is ok to vary for this exercise)
db backrow if not included on chest day

rest day

day 2 chest/tris/shoulder
Flat Bench 3 sets, 10.8.6
skull crushers or tricep extension 3 sets, 10,8,8
Military press or dumbell shoulder press 3 sets 10,8,6
and i personally like to have at LEAST one pull exercise on bench days so i include dumbell backrows, same set/rep range. if you dont want to include this on this day that is perfectly fine, but you should include it in your back/bi day if not
pushups1X failure

rest day

day 3 legs!!
warm up(remember this is only to warm your legs up and get the blood flowing, not to tire yourself out!)
Squat 3 sets 10,8,6
leg press 2X12
situps or weighted situps 3X15
squats usually do a good job of kicking your ass, you should be exhausted by the end of your leg day :D

another rest day, then start over.

also remember that results will come from #1(most important) diet! #2 REST!! #3 consistency! work hard and get your form down, you should be seeing results very soon. btw i know what its like to be the fat kid! i weighed 190 in the 7th grade!! results will come you just have to put in the work! good luck and happy lifting!

first day with no buds, 11/17, need a new job. 1 down 13 to go.

Thanks for the reply, it did help, I'll try doing those, but other people; feel free to share your insight as well!