There are currently a handful of modeling agencies in Washington, including:
Heffner Management
Seattle Models Guild
TCM Models & Talent
The Pink Light Model & Talent Agency
THE Artist Agency
There are hundreds if not thousands of agencies out there, especially if you are asking how many there are worldwide.
Many modeling agencies will not accept a 13 year old. But, there are many big agencies in New York, Flordia, and California.
There are no modeling agencies in the OC. You will need to seek out agencies in Los Angeles and San Diego.
It sounds like you'll want to look into glamour modeling. There aren't many modeling agencies that have glamour modeling divisions but there are online glamour modeling agencies you may want to look into. You can do an online search for glamour modeling agencies in Portland and see what comes up.
There are hundreds of agencies in the United States. Just about all 50 states has at least one modeling agency, while the larger markets have dozens.
Unfortunately, the Michigan area is not a viable modeling market, which means that there are not many credible, legit and reputable modeling agencies for teens. There are one or two agencies that appear legit but they do not specialize in teen models.
Petite modeling agencies are few and far in between because there is no demand for them but you can try a shot at commercial/print modeling agencies: - Angie's Model & Talent Agency
Yes. There are many modeling agencies in London, however there are height requirements that must be met--even for teens. This link contains all the modeling agencies in the London area. Be sure to check their websites and note the requirements needed in order to submit your teen: http://www.kmodels.com/London-modeling-agencies-links1.htm
Skip modeling schools and deal directly with the modeling agencies. Here is a link to modeling agencies in Arizona, whose websites you can check out to see what their requirements are and what photos you need to send in: http://www.joeedelman.com/agencies/agency_az.php
If you are looking for modeling agencies in Newry, Pennsylvania, this link contains all the modeling agencies located in the Pennsylvania area: http://www.joeedelman.com/agencies/agency_pa.php
This link will show you three modeling agencies in the Mauritius area...there aren't many: http://www.jurgita.com/agencies/mauritian-agencies
No. Many agencies prefer new models to have little to no experience and many will state that modeling schools are not necessary. Agencies will train new models for free and hate dealing with bad habits that modeling school students are taught. Your best bet is to submit your photos and information to local agencies and as well as attending open casting calls.