trucking company's near portland

Best bet is a private school if you can spring for it, I went to IITR in Portland (Clackamas).
That way you aren't locked into a company that may not be working out for you, lots of starter companies have tuition reimbursement but most drivers don't stay long enough to get a full repayment of their schooling, that right there should tell you why you don't want company training to get your CDL except as a last resort.
Lot's of different driving jobs in the Portland area and all the big starter companies have terminals in and around Portland.
I started with May Trucking in Brooks (closer to Salem) but after 4 months moved to Schneider for a regional NW gig and home every Saturday.
Did that for 8 months and then landed a day-cab gig hauling woodchips and home daily.
Had to do a graveyard shift for a year before making days, been on days for a year now and enjoy working 5 days a week and home in my own bed every night.
Hope this helps you, don't worry about your age it's actually a plus in this industry, I started at 54.