My migraines are also scent, light, heat (too much time in 100+ weather is a no go for me!) and too little sleep.
My worst trigger when I was pregnant was the smell of shoe polish! My husband and I were both in the military and the boots were shined at least once a week. That was the worst 34 weeks of my life, and my husband went so far as to not only shine my boots for me, but shine them outside or in the garage, but as soon as he brought them in. WHAM! Throwing up, seeing spots, no noise please migraines were to follow.
Direct sunlight, even with really dark sunglasses, will set off migraines for me as well. Something about squinting my eyes. And any type of Avon perfume. I have to go pick out my husbands deoderant and body spray otherwise I'm a ticking time bomb.
I used to use wet, cold rags to help but one night my husband put one of those frozen but mushy (still moldable) ice packs in a towel and put in on the back of my neck. I don't know why I never thought of that before, but I could roll over to my back, put it on the pillow without a big wet spot, mold it to the crease of my neck, and fall asleep as it stays cold for HOURS! Besides meds, this is the best thing ever!
Oh, and to actually answer your last questions, yes, as I age they become worse and more frequent. If you are not on preventative meds yet, you should definitely go talk to your doctor. He/she will be able to let you know what is normal and if you should be worried about something worse (for example, my cousin thought he had migraines and he actually had a very agressive tumor). Of course, this is rare, and since you can identify triggers to your headaches this is very likely not a problem for you.