There's no problem with being older as an applicant, if anything it will help you, not hurt you. On the flip side, I think it is increasingly becoming harder for people applying straight out of undergrad.
However, I'm against the recent reverse age-discrimination in Clinical Psychology Ph.D. programs. There has been an increasing trend at selective programs to almost exclusively take people with a few years of research experience. While this ensures good research skills and some clinical experience under your belt, I feel like programs are losing quality applicants who are coming straight out of college.
Certain selective MBA programs (in which 2-3 years of experience is almost mandatory) have begun taking a few people straight out of undergrad in order to recruit superstars they might lose to other schools a few years down the line (they are given the option to defer their acceptance to gain more experience as well). They actively recruit them, will even will waive their $200 something application fee, and give them feedback on their essays if they don't get in.
I have plenty of friends who got into med school at age 21 because they know what they wanted to do and wanted to get on with their lives in order to start families. The Ph.D. + internship + post-doc process is so long as is, that lots of fresh college-grads might not be willing to put it off for another 2 years.
While it is certainly not impossible to get into a Clinical Psychology program as a recent college grad, what I have heard on the interview trail is that these just-graduated applicants are mostly the minorities at interviews, and that they have to prove to the professors that they are mature enough to handle the work (as if their age is something to be 'overcome'). It's great if you want to take time off, but it shouldn't be held against you if you don't want to take a gap in your education.
That's a bit silly in my opinion. If med students can get in at age 21 and treat patients by their third year at age 23 , there's no reason why young age should be held against an aspiring clinical psychologist. Internationally, medical students start at age 18 in many countries. The road is long enough as is, and clinical psychology as a field has enough problems as is, that's its just going to further deter the best and brightest from entering the field. Their logic is just going to be "well, 2 years post-bacc experience + 6 year Ph.D. = 8 years total. I could just finish med school and psychiatry residency in the same amount of time..."
What we need are solid public/private universities (not free-standing professional schools) to offer Psy.D.s that are clinically-focused and where you're guaranteed to graduate in 4 years, just like D.D.S. and Pharm.D. doctoral degrees. There's no reason you can't teach someone how to be a doctoral level psychologist in 4 years (if research is optional), if you can teach someone to be a licensed and practicing dentist or pharmacist in the same amount of time. This will be a big benefit to the field by attracting better candidates, ensuring quality control, and limiting the number of graduates entering the market.
That's the (one) nice thing about getting a low paid RA job-- you don't get that. I've had low paying jobs/ stipends my whole life, so now the $30k I'm bound to make as a post-doc seems like a goldmine. 
